INSTRUMENTATION

INSTRUMENTATION ACCESSORIES

TRAINING MANUAL
Course EXP-MN-SI060
Revision 0
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Instrumentation
Instrumentation accessories

INSTRUMENTATION
INSTRUMENTATION ACCESSORIES

CONTENTS

1. OBJECTIVES ..................................................................................................................6
2. ACCESSORIES FOR FITTING TRANSMITTERS...........................................................7
2.1. ISOLATING VALVES ................................................................................................7
2.1.1. Manifold.............................................................................................................7
2.1.1.1. 2-way manifolds ...........................................................................................7
2.1.1.2. 3- and 5-way manifolds ................................................................................7
2.1.1.3. The manifold and its associated transmitter .................................................8
2.2. MOUNTING BRACKET FOR REMOTE TRANSMITTER..........................................9
2.2.1. Wall mounting bracket .......................................................................................9
2.2.2. Mounting bracket for 2-inch tube .....................................................................10
2.2.3. Mounting the transmitter on the mounting bracket ..........................................10
3. TUBING .........................................................................................................................11
3.1. REMINDER ON THREADS.....................................................................................11
3.1.1. Threads ...........................................................................................................11
3.1.1.1. British Standard Pipe (BSP) threads ..........................................................11
3.1.1.2. Metric threads ............................................................................................12
3.1.1.3. National Pipe Thread (NPT) threads ..........................................................12
3.1.2. Definition of thread cutting using a threading die.............................................13
3.1.2.1. Die (also called "threading die") .................................................................13
3.1.2.2. Thread characteristics................................................................................14
3.1.2.3. Standardised thread designation................................................................14
3.1.3. Procedure for making a thread ........................................................................15
3.2. COMPRESSION COUPLINGS ...............................................................................15
3.2.1. Straight couplings ............................................................................................16
3.2.1.1. Male union..................................................................................................16
3.2.1.2. Female union .............................................................................................16
3.2.1.3. Male end fitting...........................................................................................16
3.2.1.4. Equal union ................................................................................................17
3.2.1.5. Piping penetration ......................................................................................17
3.2.2. 45° elbow couplings ........................................................................................17
3.2.3. 90° elbow couplings ........................................................................................17
3.2.3.1. Union elbow ...............................................................................................17
3.2.3.2. Male elbow coupling...................................................................................18
3.2.3.3. Female elbow coupling ..............................................................................18
3.2.4. Tees ................................................................................................................18
3.2.4.1. Union Tee...................................................................................................18
3.2.4.2. Male Tee ....................................................................................................18
3.2.4.3. Female Tee ................................................................................................18
3.3. QUICK-CONNECT COUPLINGS ............................................................................19
3.3.1. Straight coupling..............................................................................................19
3.3.2. Elbow couplings ..............................................................................................19
3.3.2.1. 90° elbow couplings ...................................................................................19
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3.3.2.2. 45° elbow couplings ...................................................................................20

3.3.3. Tees ................................................................................................................20
4. CONNECTING INSTRUMENTATION TUBES TO COMPRESSION COUPLINGS.......21
4.1. PRECRIMPING THE TUBE ....................................................................................21
4.2. SEALING OF COUPLINGS.....................................................................................23
4.3. INSTRUMENTATION TUBES .................................................................................23
4.3.1. Instrumentation tubing specifications ..............................................................23
4.3.2. Polyamide tube................................................................................................26
4.3.3. Copper tube.....................................................................................................27
5. THE DIFFERENT CABLES USED IN INSTRUMENTATION.........................................28
5.1. WHAT IS A CABLE MADE OF? ..............................................................................28
5.1.1. The conductor .................................................................................................28
5.1.2. The insulation ..................................................................................................29
5.1.2.1. Properties...................................................................................................29
5.1.2.2. Insulation material ......................................................................................29
5.1.3. Mechanical protection......................................................................................30
5.1.4. Sheathed cables..............................................................................................31
5.1.5. Armoured cables .............................................................................................32
5.1.6. Mineral-insulated cables..................................................................................33
5.2. TRANSMITTER POWER SUPPLY CABLES ..........................................................34
5.2.1. Cable U1000 R2V ...........................................................................................34
5.2.1.1. Installation ..................................................................................................34
5.2.1.2. Identification of conductors.........................................................................34
5.2.1.3. Electrical characteristics.............................................................................35
5.2.2. Flexible core cable HO7RN-F..........................................................................36
5.2.2.1. Installation ..................................................................................................36
5.2.2.2. Identification of conductors.........................................................................36
5.2.2.3. Electrical characteristics.............................................................................37
5.3. INSTRUMENTATION CABLES...............................................................................38
5.3.1. Meaning of instrumentation cable coding ........................................................38
5.3.2. Conductor standard colours ............................................................................38
5.3.3. Construction of an instrumentation cable ........................................................39
5.3.3.1. Conductor core...........................................................................................40
5.3.3.2. Insulation....................................................................................................41
5.3.3.3. Protective sheaths......................................................................................42
5.3.3.4. The screen .................................................................................................43
5.3.3.5. Mechanical protection ................................................................................43
5.3.4. Examples of instrumentation cables ................................................................44
5.3.5. Summary .........................................................................................................45
5.4. SPECIAL INSTRUMENTATION CABLES...............................................................46
5.4.1. Reminder of the thermocouple measuring principle ........................................46
5.4.2. Thermocouple compensation cables ...............................................................47
5.4.2.1. Compensation cable codings .....................................................................48
5.4.2.2. Colour codings ...........................................................................................49
5.4.3. Network cables................................................................................................50
5.4.3.1. Profibus cable ............................................................................................50
5.4.3.2. Ethernet cable ............................................................................................50
5.4.3.3. Determining the type of RJ45 cable ...........................................................54

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5.4.3.4. RJ45 cable categories................................................................................54

5.4.3.5. Making your RJ45 cable.............................................................................55
5.4.3.6. Reminder on HUBS and SWITCHES .........................................................61
6. CONNECTING INSTRUMENTATION CABLES ............................................................64
6.1. CABLE GLANDS.....................................................................................................64
6.1.1. Introduction......................................................................................................64
6.1.2. Procedure for electrically connecting a transmitter..........................................65
6.2. CONNECTING A CABLE TO A COMPRESSION COUPLING ...............................67
7. CABLE BRACKET - CABLE TRAY................................................................................75
7.1. GENERAL ...............................................................................................................75
7.2. LAYING CABLES ....................................................................................................76
7.3. LADDER RACK.......................................................................................................77
7.4. THE DIFFERENT TYPES OF CABLE TRAYS........................................................79
7.4.1. Types of cable trays available .........................................................................79
7.4.1.1. Ladder cable trays......................................................................................80
7.4.1.2. Solid bottom cable trays .............................................................................80
7.4.1.3. Trough cable trays .....................................................................................81
7.4.1.4. Channel cable trays ...................................................................................81
7.4.1.5. Wire mesh cable trays................................................................................82
7.4.1.6. Single rail cable trays .................................................................................83
7.4.2. Materials / finishes available for the various cable tray systems .....................83
7.4.3. Cable tray mounting accessories ....................................................................84
7.4.4. How to construct a flat 90° bend......................................................................85
7.4.5. How to construct a Tee piece ..........................................................................87
7.4.6. How to construct a 90° external bend..............................................................88
7.4.7. How to construct a 90° internal bend...............................................................88
7.4.8. How to construct an offset ...............................................................................89
7.4.9. Earthing the cable trays...................................................................................90
8. LOW VOLTAGE CABLES..............................................................................................91
8.1. CABLE TERMINATIONS ........................................................................................91
8.2. REMOVING THE INSULATION ..............................................................................93
8.2.1. Removing the sheath using side cutting pliers ................................................93
8.2.2. Stripping insulated wires with a stripping knife ................................................94
8.2.3. Wire stripping tools ..........................................................................................95
8.3. TYPES OF TERMINATIONS AND CONNECTIONS...............................................97
8.3.1. Mechanical terminations..................................................................................97
8.3.1.1. Pillar terminals............................................................................................97
8.3.1.2. Screw terminals and nut-bolt terminals ......................................................98
8.3.1.3. Claw washers (also know as toothed washers)..........................................99
8.3.1.4. Strip connectors .........................................................................................99
8.3.1.5. Split-bolt connectors.................................................................................100
8.3.2. .......................................................................................................................100
8.3.3. Crimped connections.....................................................................................101
8.3.3.1. Crimped lugs ............................................................................................101
8.3.3.2. Crimping tools ..........................................................................................103
8.3.4. Making a crimped connection........................................................................104
8.3.5. Use the correct crimping method...................................................................106
9. FIGURES.....................................................................................................................111

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10. TABLES .....................................................................................................................115

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1. OBJECTIVES
This course aims to teach a future instrument technician about the accessories necessary
for the instrumentation equipment present on an industrial site in the oil industry.

At the end of the course, in the instrumentation and standards field, the participant must:

Know the principal instrumentation accessories

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2. ACCESSORIES FOR FITTING TRANSMITTERS

2.1. ISOLATING VALVES

2.1.1. Manifold

The manifold is quite simply an assembly of isolating valves on a same block. Its main job
is to isolate a pressure transmitter so that its zero can be calibrated.

2.1.1.1. 2-way manifolds

The 2-way manifold is used for "conventional" pressure transmitters. It has a transmitter
HP isolating valve and a drain valve.

This type of manifold is very rarely used.

Figure 1: 2-way manifold

2.1.1.2. 3- and 5-way manifolds

The 3- and 5-way manifolds are much used in the instrumentation field, they connect
directly to the differential pressure transmitters.

The 3-way manifold combines the isolating and bypass functions.

Using two valves (right and left), we isolate the HP and the LP sides of the transmitter, and
we balance the two chambers (HP and LP) using the bypass valve (middle): this facilitates
the transmitter zero check when the two measurement chambers are well balanced.

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Figure 2: 3-way manifold

The 5-way manifold 5 is identical to the 3-way manifold except that we have added two
drain valves. These allow each of the transmitter's measurement chambers to be drained.

Figure 3: 5-way manifold

2.1.1.3. The manifold and its associated transmitter

In this example, the manifold is mounted directly on the transmitter by

means of screws supplied with the manifold.

Figure 4: 3-way manifold associated with a transmitter

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2.2. MOUNTING BRACKET FOR REMOTE TRANSMITTER

It is important to talk about the mounting brackets which are available.

When ordering a remote transmitter, do not forget that the mounting bracket is an option.

There are two types of mounting brackets:

• Wall mounting bracket,

• Mounting bracket for 2-inch tube.

2.2.1. Wall mounting bracket

Figure 5: Wall mounting bracket for a transmitter

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2.2.2. Mounting bracket for 2-inch tube

Figure 6: Mounting bracket for 2" tube for a transmitter

2.2.3. Mounting the transmitter on the mounting bracket

Figure 7: Mounting the transmitter on the mounting bracket

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3. TUBING

3.1. REMINDER ON THREADS

3.1.1. Threads

3.1.1.1. British Standard Pipe (BSP) threads

These "Gas" profile threads are of two types:

• Parallel: they fit into the same parallel internal thread. The sealing is provided by
an incorporated annular seal (or by a sealing washer).

• Taper: they fit into the same parallel or tapered internal thread. The sealing is
provided by a precoating on the thread.

Thread designations

• BSP Parallel (BSPP): G followed by the denomination, as per the ISO 228-1
standard. Example: a 1/8 BSP parallel thread is written G1/8

• BSP Taper (BSPT): R followed by the denomination, as per the ISO 7-1
standard. Example: a 1/8 BSP taper thread is written R1/8

• Internal threads:

• BSP parallel: G
followed by the
designation

• BSP taper: Rc
followed by the
designation

Figure 8: BSP threads

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3.1.1.2. Metric threads

These ISO profile threads are parallel threads. They fit into the
same parallel internal thread. The sealing is provided by an
incorporated annular seal (or by a sealing washer).

Thread designations: M followed by the diameter and pitch

values in millimetres, separated by the multiplication sign, as
per the ISO 68-1 and ISO 965-1 standards.

Example: M7x1

Figure 9: Metric threads

3.1.1.3. National Pipe Thread (NPT) threads

This is an American standard with taper threads. They fit into

the same tapered internal thread. The sealing is provided by
a precoating on the thread.

Figure 10: NPT threads

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3.1.2. Definition of thread cutting using a threading die

Thread cutting is a manual machining process which involves the removal of metal chips.
Its consists of cutting helical-shaped grooves in a previously calibrated cylindrical
workpiece. The part at the end of the operation is a screw.

Initial state (calibrated cylinder) Final state (screw)

Figure 11: Definition of the thread

3.1.2.1. Die (also called "threading die")

Different types of dies:

The die is in the form of a nut in which teeth are cut.

The types of dies depend on:

Pitch direction

right-hand dies

left-hand dies Closed circular die

Pitch type

fine pitch dies

normal pitch dies

Figure 12: Circular dies Open circular die

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Die stock

The die stock is a cage which holds the die. It has handles which facilitate its use.

Figure 13: Die stock

3.1.2.2. Thread characteristics

A thread is characterised by:

• Profile (triangular, trapezoidal, round, gas)

• Pitch

• Thread direction

• Length

3.1.2.3. Standardised thread designation

The standardised thread designation consists of:

• System or profile

• Nominal diameter

• Pitch (distance between two consecutive thread crests)

Example: M 10 X 1.5

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3.1.3. Procedure for making a thread

1. Engage the die.

2. Ensure that the die is the correct way

round and that it is centred on the
workpiece.

3. Lubricate with cutting oil.

4. Turn the die in the direction of the cutting

(from left to right) to make the thread.

5. Reverse the movement from time to time

to break the chips.

Figure 14: Making a thread

3.2. COMPRESSION COUPLINGS

This type of coupling is used to connect pipes

made of Stainless steel or Carbon steel.

As their name indicates, compression couplings form a tight seal by applying a

compression force to pipes and to the pipe coupling. The coupling is compressed against
the pipe with sufficient force to eliminate all the space remaining in the joint, thus
preventing fluid leaks.

The compression coupling consists of an external "compression nut" and an internal "ring"
or "olive". When the nut is tightened it becomes fixed on the olive and makes it take the
shape of the circumference of the pipe. The shape and the material of the olives can vary
according to the pipe material. In order to function correctly, the olive must be the right way
round. The olive is normally placed so that the longer inclined side is furthest away from
the nut.

Nut Front ring

Rear ring

Figure 15 : Nuts and rings

The couplings produced by some manufacturers only have a single olive. On our sites we
use "Swagelok" connections with 2 rings (front and rear).

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All these couplings are those most commonly used. We will see in the next chapter how to
connect our instrumentation tubes to these couplings.

The ring or olive couplings are the most reliable and the most solid I have met.

There are also plastic quick-connect couplings. As far as maintenance is concerned, they
are not the best equipment since they can break in your hands because they very quickly
deteriorate due to heat or to the sun's rays.

3.2.1. Straight couplings

3.2.1.1. Male union

Figure 16: Male union

3.2.1.2. Female union

Figure 17: Female union

3.2.1.3. Male end fitting

Figure 18: Male end fitting for tube

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3.2.1.4. Equal union

Figure 19: Equal union fitting

3.2.1.5. Piping penetration

Figure 20: Piping penetration

The "piping penetration" coupling is very practical when you want to get air into a box
(e.g. distributor box).

3.2.2. 45° elbow couplings

Figure 21: 45° elbow coupling

3.2.3. 90° elbow couplings

3.2.3.1. Union elbow

Figure 22: 90° union elbow

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3.2.3.2. Male elbow coupling

Figure 23: 90° male elbow coupling

3.2.3.3. Female elbow coupling

Figure 24: 90° female elbow coupling

3.2.4. Tees

3.2.4.1. Union Tee

Figure 25: Union Tee

3.2.4.2. Male Tee

Figure 26: Male Tee

3.2.4.3. Female Tee

Figure 27: Female Tee

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3.3. QUICK-CONNECT COUPLINGS

This type of coupling is used to connect metric plastic tubes.

The tube must be pushed fully home in the coupling.

It provides instant connection and sealing.

• To disconnect it, push the external button and pull the tube.

• Use a tube cutter for a good, straight cut

3.3.1. Straight coupling

Figure 28: Straight quick-connect coupling

3.3.2. Elbow couplings

3.3.2.1. 90° elbow couplings

Figure 29: 90° elbow quick-connect coupling

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3.3.2.2. 45° elbow couplings

Figure 30: 45° elbow quick-connect coupling

3.3.3. Tees

Figure 31: Quick-connect tees

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4. CONNECTING INSTRUMENTATION TUBES TO

COMPRESSION COUPLINGS
Before inserting the tube in the coupling and tightening the nut on the ring, the ring must
be precrimped on the tube.

To do this we have a very practical tool called a "precrimping tool"

4.1. PRECRIMPING THE TUBE

The "precrimping tool" is shown in the figure

Figure 32: Tube precrimping tool

We will now use the following examples to illustrate the procedure.

Firstly, we place the nut and the ring on the tube

Figure 33: Insertion of the tube in the precrimping tool

The tube must then be inserted in the precrimping tool. We ensure that it firmly abuts on
the shoulder of the crimping tube and we hand tighten the nut

We maintain the body of the precrimping tool and tighten the nut almost two turns with a
spanner.

Figure 34: Crimping the tube in the tool

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And finally, we can:

Unscrew the nut

Remove the tube with the precrimped rings from the tools.

Once the tube has been precrimped we can insert our tube with its precrimped ring into
the coupling we wish to connect.

Figure 35: Insertion of the crimped tube into a coupling

Furthermore, it is essential for the integrity of the coupling that we do not apply
excessive force when tightening the nut. If the connection is too tight, the olive will
become distorted resulting in leaks.

Excessive tightening is the main cause of leaks in compression couplings.

As a general rule, a compression coupling must initially be hand tightened, then tightened
a quarter turn with a spanner. The coupling must then be tested and if we observe a slight
seepage, the coupling must be slowly tightened a little more until the seepage stops.

If during assembly and disassembly of these couplings you hear a squeaking noise
when tightening with a spanner, it is too late, the coupling has been destroyed. The
only solution is to replace it.

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4.2. SEALING OF COUPLINGS

Here is a short reminder because, on worksites, I have already seen instrument

technicians connect instruments to couplings without using Teflon.

This is important because it can result in large measurement errors if there are leaks on
the instrumentation couplings.

Here is the procedure to be followed to apply Teflon on all types of couplings:

Figure 36: Application of Teflon (PTFE) on all couplings

The Teflon tape must be applied in the opposite direction to the

thread.

"Loctite" is now also used to replace Teflon but I would not recommend it
because the couplings become difficult to remove.

Figure 37: "Loctite" for sealing the couplings

4.3. INSTRUMENTATION TUBES

4.3.1. Instrumentation tubing specifications

Remember that to connect transmitters to the process the pipes must not exceed ½ inch in
diameter. 75% of the time the transmitters are connected using couplings with NPT
threads.

The following tables show all the types of tube connections, the diameters are given for
each component according to the piping class (the class is the rating).

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Note:

NPT (National Pipe Thread) is an American standard for taper threads (NPT) and NPS
(Nominal Pipe Size) for straight threads for connecting piping and couplings. The
ANSI/ASME B1.20.1 standard covers 60 degree NPS threads with flat thread crest for
sizes from 1/16 inch to 24 inches. The taper angle for all NPT threads is 3/4 inch per foot.
The 1/8, 1/4, 3/8, 1/2, 3/4, 1, 1 1/4, 1 1/2 and 2 inch sizes are frequently used on pipes and
couplings produced by most American suppliers.

Smaller sizes are sometimes used for compressed air. Larger sizes are rarely used
because other connection methods are more practical above 3 inches in most
applications.

NPS threads are not tight in the internal diameter of the pipe (Schedule 40). Due to the
pipe wall thickness the real thread diameter is greater than the NPS threads, and
considerably greater for small NPS threads.

Other pipe schedules have a different wall thickness but the outer diameter (OD) and the
thread profile remain the same and therefore the internal diameter of the pipe is different to
the nominal diameter.

Figure 38: Diagram of NPT coupling with internal and external threads

4.3.2. Polyamide tube

Polyamide tubes are increasingly used

today and are replacing copper tube for
instrument air or gas supply.

They are obviously quicker and easier to

replace when worn than copper.

Figure 39: Polyamide tube

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This type of tube can resist a pressure of up to 14 bars and a temperature of 70°C.

The diameters most commonly used for instrumentation are 4/6 mm, 6/8mm, 8/10mm or
even 10/12mm.

The diameters of these tubes are internal diameter/outer diameter.

4.3.3. Copper tube

See the engineering course on "Piping".

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5. THE DIFFERENT CABLES USED IN INSTRUMENTATION

5.1. WHAT IS A CABLE MADE OF?

Cables are intended to transport electric current. They must be able to fulfil this role safely
with respect to equipment and personnel.

Cables generally consist of three main parts:

Conductor

Insulation

Mechanical protection

Figure 40: Construction of a

‘standard’ cable

The conductor transports electric energy. Several conductors sharing the same cable will
be separated and isolated from each other.

Should the mechanical protection be damaged, the insulation (if the insulation sheath is
not damaged) must not be affected. In this case, the insulation sheath is the only effective
protection and it also provides mechanical protection.

5.1.1. The conductor

The conductor must have a low resistivity (low resistance), this characteristic is provided
by certain metals.

The conductor must also have other physical

properties. It must be ductile and flexible. A
ductile metal may be pulled and drawn without
breaking, this is a basic quality which is
required when manufacturing cables. However,
there are other factors that a manufacturer (or a
user) requires of a cable,these concern the
weight and cost. Silver is thus one of the best
conducting metals but it is easy to understand
why copper conductors are preferred.

Figure 41: Cu conductor/Al conductor

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Aluminium is also increasingly used as a metal conductor. Aluminium has a resistivity 1.6
times greater than copper, and the same current therefore requires a larger cross-
sectional area, however aluminium is (far) less expensive and much lighter, (you can
clearly feel the difference when you pull the cables).

5.1.2. The insulation

5.1.2.1. Properties

The main function of the insulation on the conductive core of a cable is to "prevent the
electricity from escaping" from the cable in question, and to prevent any external contact
with a live part (i.e. a person touching the conductor).

The insulation is required to be flexible, to support differences in temperature and resist

mechanical constraints and external attack. The main property required is however high
electric (or dielectric) resistance (or resistivity).

The insulation of an electrical energy transport cable must have the following properties

High electric resistance

A certain amount of flexibility

Resistance to temperature changes

Mechanical resistance to impact and external aggression (chemical, atmospheric,

etc.)

5.1.2.2. Insulation material

PVC is the most commonly used material. PVC is the abbreviation for Polyvinyl chloride.

The principal advantages of PVC are:

Good insulating quality (high resistance)

Waterproof

Low cost

Easy to colour

Good mechanical strength

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The main disadvantages of PVC are:

Softens above 70°C

Becomes brittle below 0°C3

Some qualities of PVC can resist temperatures of up to 85°C, but most remain within the
range indicated above (0 - 70°C)

The other materials used as cable insulations are, among others:

Vulcanised rubber

Synthetic rubber

Silicone (derived from silicon)

Paper (treated with resin)

Paper insulation was used in HV cables but has now been replaced by synthetic rubber for
almost all applications. It is however still used in some flexible cables where a high
flexibility is required.

Synthetic rubbers are used for high or low temperatures.

Silicone is used for very high temperatures, i.e. approximately 150°C.

5.1.3. Mechanical protection

The main function of the mechanical protection is to prevent damage to the conductive
core's insulation, which could cause electrocution, sparks or start a fire.

The cable sheath

The sheath is the cable's mechanical protection.

The type of cable shown is used to connect bedside lamps or your washing machine,
fridge, etc.

Most cable protective sheaths are made of PVC; rubber is used for cables requiring extra
flexibility. This type of cable is mainly used for domestic distribution, and in tertiary
applications and offices where there little risk of mechanical damage.

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Figure 42: Different cable sheaths (mechanical protection)

This paragraph gives a general description of the composition and manufacture of cables.
We will consider other types of mechanical protection later on.

5.1.4. Sheathed cables

These are the cables which you see "lying around" at home, in stores, in the office, or
even on worksites (during construction). This is the cheapest and quickest means of laying
cables. The cables are protected by their own sheaths only, thus providing minimal
mechanical protection.

Most sheathed cables have an external PVC sheath which may also be made of:

Synthetic or natural rubber

Agglomerate PVC

Braid (metal or other)

The 3 cable types shown correspond to:

a) a stranded core conductor

b) a rigid core conductor with ground (earth) wire

c) three rigid core conductors with a fourth ground conductor

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Figure 43: Different PVC sheaths

5.1.5. Armoured cables

The cables are mechanically protected by a steel armour if there is a risk of attack (impact,
compression, rodents, etc.).

This is the type of cable which is frequently installed in our industry due to the permanent
risk of mechanical damage.

The conductors and their insulation are protected by a metal or even plastic sheath,
armour or braid (term as applicable). A cable may have several sheaths/armoured
coverings. However, this additional mechanical protection more generally consists of steel
wire armour (SWA) as shown in the figure.

Figure 44: Steel wire armoured (SWA) cable

The armour may also consist of

A helically-wound steel tape.

An aluminimum tape (or sheath)

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These armoured cables may be installed directly in contact with equipment and/or laid in
cable trays, trenches, conduits, etc.

5.1.6. Mineral-insulated cables

These cables have a mechanical protection which consists of a metal sheath, which is why
it is specified in their designation: mineral insulated and metal sheathed cables. These
types of cables can be found in our industry with "fire resistant cables", i.e. cables used to
resist fire in safety circuits and areas where there is a risk. In the instrumentation field, we
use them as thermocouple cables installed in various environments

There are two types of metal sheaths:

Mineral Insulated Copper Sheath (MICS).

Mineral Insulated Aluminium Sheath (MIAS)

The conductors in this type of cable are insulated at high

pressure using magnesium oxide powder

Figure 45: Cross section of high temperature resistant cables

These cables generally have an additional PVC sleeve over the metal sheath to protect
against corrosion and provide good resistance to damp atmospheres. These cables are
connected using special cable glands to avoid the moisture entering the cable.

Figure 46: Construction of a mineral-insulated cable

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5.2. TRANSMITTER POWER SUPPLY CABLES

‘G’ for ground (earth) indicates that one of the conductors has a green and yellow coloured
insulation. E.g.: 3G1.5 which indicates a cable with 3 x 1.5 mm² conductors (one of which
is a yellow/green conductor)

5.2.1. Cable U1000 R2V

Figure 47: Conventional cable U1000 R2V

These cables are designed for normal use in industry and are particularly recommended in
fixed low voltage energy distribution installations. Multi-conductor cables are well-adapted
to remote command and control installations. When there is a risk of chemical attack
(corrosion) or prolonged immersion, use 1000 RGPFV. When there is a high ambient
temperature, apply the correction factor.

5.2.1.1. Installation

These cables can be used in cable trays, channels and troughs or fixed to the walls. They
can be buried if they have additional mechanical protection.

Minimum bend radius

For fixed installation: 6 times the external diameter. During installation, this value must be
doubled.

5.2.1.2. Identification of conductors

2 conductors: blue + brown

3 conductors = Y / G + blue + brown or brown + black + grey

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5.2.1.3. Electrical characteristics

Number of Admissible current External diameter

ΔU
conductors (A) (mm)
(cosϕ Weight
Cross-
0.8) (kg/km)
sectional Buried Open air Core Min. Max.
V/A.km
area (mm²)
1 x 1.5 31 24 24.8 1.37 - 6.4 48
1 x 2.5 41 33 15.3 1.76 - 6.8 60
1x4 53 45 9.2 2.23 - 7.2 78
1x6 66 58 6.4 2.90 - 8.2 102
1 x 10 87 80 3.7 3.70 - 9.2 146
1 x 16 113 107 2.4 4.80 - 10.5 207
1 x 25 144 138 1.40 6.24 - 10.92 302
1 x 35 174 169 1.00 7.38 - 12.06 398
1 x 50 206 207 0.78 8.10 - 12.76 514
1 x 70 254 268 0.56 9.80 - 14.66 724
1 x 95 301 328 0.43 11.30 - 16.36 975
1 x 120 343 382 0.36 12.70 - 17.96 1219
1 x 150 387 441 0.31 14.10 - 19.96 1485
1 x 185 434 506 0.26 15.70 - 21.96 1844
1 x 240 501 599 0.22 18 - 24.66 2373
1 x 300 565 693 0.19 20.10 - 27.16 2957
1 x 400 662 825 0.17 23.50 - 31.36 3846
1x 500 750 946 0.15 27.1 - 35.36 4872
1 x 630 850 1088 0.14 30.15 - 39.21 6266
2 x 1.5 37 26 24.8 1.37 8.8 10.5 129
2 x 2.5 48 36 14.8 1.76 9.6 11.5 162
2x4 63 49 9.2 2.23 10.5 13.0 209
2x6 80 63 6.2 2.90 11.5 14.0 282
2 x 10 104 86 3.7 3.70 13.0 16.0 397
2 x 16 136 115 2.4 4.80 15.0 18.5 553
2 x 25 173 149 1.3 6.24 17.5 21.02 900
2 x 35 208 185 1.15 7.38 19.5 23.35 1167
3 G / x 1.5 31 23 24.8 1.37 9.2 11.0 130
3 G / x 2.5 41 31 14.8 1.76 10.0 12.5 170
3G/x4 53 42 9.2 2.23 11.0 13.5 230
3G/x6 66 54 6.2 2.90 12.0 15.0 310
3 G / x 10 87 75 8.7 3.70 13.5 17.0 460
3 G / x 16 113 100 2.4 4.80 15.5 16.5 660
3 G / x 25 144 127 1.37 6.24 19.0 22.39 1117
3 x 35 174 158 1.00 7.38 21.0 24.9 1464

Table 1: Electrical characteristics of cable U1000 R2V

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5.2.2. Flexible core cable HO7RN-F

Figure 48: Cable HO7 RN-F

This cable is particularly well adapted as a power supply cable for mobile site equipment,
electric tools and construction worksites. It can be used up to 0.6/1KV for protected fixed
installations and as power supply cable for motors for lift equipment and similar equipment.

5.2.2.1. Installation

Cable designed to operate out of doors. When it is buried, provide a mechanical protection
(trough, conduit, etc.).

Bend radius

In use: 6 to 8 times the external diameter of the cable. In static use: 3 times the external
diameter.

5.2.2.2. Identification of conductors

1 conductor = black

2 conductors = blue + brown

3 conductors = Y/G + blue + brown

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5.2.2.3. Electrical characteristics

Number of Admissible ΔU External diameter

conductors (mm) Weight
current (cosϕ 0.8)
Cross-sectional (kg/km)
area (mm²) (A) V/A.km Core Min. Max.
1 x 1.5 23 23.3 1.5 5.7 7.1 50
1 x 2.5 32 14.0 1.9 6.3 7.9 66
1x4 43 8.7 2.5 7.2 9.0 94
1x6 56 5.9 3.0 7.9 9.8 109
1 x 10 77 3.4 3.8 9.5 11.9 182
1 x 16 102 2.2 5.0 10.8 13.4 256
1 x 25 136 1.4 6.3 12.7 15.8 369
1 x 35 168 1.04 7.6 14.3 17.9 482
1 x 50 203 0.75 9.0 16.5 20.6 662
1 x 70 254 0.56 10.8 18.6 23.3 895
1 x 95 315 0.44 12.7 20.8 26.0 1160
1 x 120 363 0.36 13.9 22.8 28.6 1430
1 x 150 416 0.31 15.9 25.2 31.4 1740
1 x 185 475 0.28 17.7 27.6 34.4 2160
1 x 240 559 0.23 19.4 30.6 38.3 2730
1 x 300 637 0.20 23.0 38.5 41.9 3480
1 x 400 746 0.18 26.0 37.4 46.8 4510
1x 500 833 0.16 30.0 41.3 52.0 5700
2x1 18 39.4 1.3 7.7 10.0 99
2 x 1.5 23 27.0 1.5 8.5 11.0 111
2 x 2.5 32 16.2 1.9 10.2 13.1 161
2x4 43 10.1 2.5 11.8 15.1 238
2x6 56 6.7 3.0 13.1 16.8 279
2 x 10 77 3.8 3.8 17.7 22.6 538
2 x 16 102 2.5 5.0 20.2 25.7 744
2 x 25 136 1.68 6.3 24.3 30.7 1074
3G1 18 39.4 1.3 8.3 10.7 117
3 G 1.5 23 27.0 1.5 9.2 11.9 134
3 G 2.5 32 16.2 1.9 10.9 14.0 195
3G4 43 10.1 2.5 12.7 16.2 290
3G6 56 7.0 3.0 14.1 18.0 346
3 G 10 77 4.0 3.8 19.1 24.2 663
3 G 16 102 2.5 5.0 21.8 27.6 924
3 G 25 136 1.7 6.3 26.1 33.0 1345
3 G 35 168 1.21 7.6 29.3 37.1 1760
3 G 50 203 0.87 9.0 34.1 42.9 2390
3 G 70 262 0.64 10.8 38.4 48.3 3110
3 G 95 320 0.50 12.7 43.3 54.0 4170
3 G 120 373 0.40 13.9 47.4 60.0 5080
3 G 150 432 0.35 15.9 52.0 66.0 6220
Table 2: Electrical characteristics of cable HO7 RN-F
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5.3. INSTRUMENTATION CABLES

5.3.1. Meaning of instrumentation cable coding

Instrumentation cables covered by the NF M 87-202 standard are used in the oil industry
to transmit AC or DC analogue signals.

They are of the PVC/PVC type and can be non armoured, armoured or lead-sheathed
armoured.

Non armoured cables are used when there is no risk of mechanical deterioration.

Armoured cables are used when there is a risk of mechanical deterioration.

Lead-sheathed armoured cables are used when there is a risk of contact with
aromatic hydrocarbons.

Meaning of the code consisting of 5 series of 2 figures or letters:

1st series = number of pairs, triplets or quads: 01 to 27

2nd series = pair (IP), triplet (IT), quad (IQ)

3rd series = conductive core 05 (1 wire 0.8 mm) or 09 (7 wires 0.4 mm) or
15 (7 wires 0.52 mm)

4th series = general screen (RG), individual screen + general screen (EI)

5th series = mechanical protection: non armoured (SF), with armour (FA), with lead
+ armour (PF)

5.3.2. Conductor standard colours

1 pair: white - red

1 triplet: white - red - blue

1 quad: white - red - blue - yellow

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5.3.3. Construction of an instrumentation cable

Figure 49: Exploded view of an instrumentation cable

Core: Central metal part of a conductor (copper core) which can be:

• solid: a single wire

• stranded core: formed of several strands twisted together into one or

more larger strands. Depending on the number of strands, the core is said
to be rigid or flexible.

Screen: Individual screen (if applicable) and general screen (polyester tape +
aluminium screen): Al/polyester tape with tinned copper drain strand (7x0.20
mm)

Sheath: Lead in the presence of aromatic hydrocarbons (PVC outer sheath)

Insulation: Insulating material (PVC insulation) surrounding the core of a

conductor and designed to insulate it.

Armour: Central part providing the mechanical protection for the conductors
(steel tapes). Consisting of steel tapes or steel wires spirally wound around
the cable, above the sheath and generally with a protective layer (paraffin-
impregnated paper) between them.

Drain wires: For electrical continuity.

Mechanical protection: Grey (where applicable) PVC, PVC-HR oversheath

(PVC inner sheath)

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5.3.3.1. Conductor core

The core must satisfy the following conditions:

Good conductivity to reduce losses when transporting energy. The

materials must therefore be carefully chosen (maximum values of ρ)

• copper: ρ = 18.51 mΩ.mm²/m at 20°C

• aluminium: ρ = 29.41 mΩ.mm²/m at 20°C

Mechanical strength sufficient to prevent the conductor breaking under the

forces applied during installation, attachment and tightening of the
conductors.

Good flexibility to simplify the transit of the conductors in the conduits, to

keep to the piping route, and to supply the mobile equipment.

Good corrosion resistance due to atmospheric agents and chemical agents.

Good reliability of the connections due to a good resistance to the physico-

chemical effects of the contacts.

The standard defines a range of nominal cross-sectional areas for the conductor cores and
divides them into four classes in order of flexibility.

Class 1: solid and rigid

Class 2: rigid, stranded

Class 5: flexible

Class 6: flexible (or flexible ‘+’, e.g. used for arc welding cables, or cables on coiling
units)

Nominal Conductor cores Nominal Conductor cores

cross- Number of stands x strand diameter cross- Number of stands x strand diameter
sectional in mm sectional in mm
area (mm²) Class 1 Class 2 area (mm²) Class 5 Class 6
1.5 1 x 1.38 7 x 0.50 0.5 16 x 0.20 28 x 0.15
2.5 1 x 1.78 7 x 0.67 0.75 24 x 0.20 42 x 0.15
1 32 x 0,20 56 x 0.15
1.5 30 x 0.25 85 x 0.15
2.5 50 x 0.25 140 x 0.15

Table 3: Construction of conductor cores

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5.3.3.2. Insulation

This insulation must provide a good insulation for the conductor core and have the
following properties:

General properties for good insulation

• high resistivity

• excellent dielectric strength

• low electric losses

Specific properties for the use of conductors and cables

• Good resistance to aging

• Good resistance to cold, heat and fire

• Not sensitive to vibrations and impacts

• Good reactions in case of attack by chemicals

Main materials:

Thermoplastic materials

The temperature causes a reversible variation in plasticity. This applies for:

Polyvinyl chloride (PVC) which is frequently used due to its good electrical
and mechanical properties and its resistance to cold, heat aging, water and
commonly-used chemicals and to flame spread. However, the combustion
of this substance involves the emission of toxic and corrosive products.

Polythene (PE), whose remarkable properties make it a preferred insulation

material (particularly for HV). The combustion of this material does not
involve the emission of toxic or corrosive products.

Cross-linked elastomers and polymers

They are elastic, i.e. able to accept major deformations. This applies for:

Cross-linked polythene (PR), mainly used for temporary overloads and

unfavourable heat environments. It must also be noted that this material has
a good resistance to cold and does not give off corrosive gases during
combustion.

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Ethylene-propylene copolymers, for rigid cables and particularly for flexible

cables. This material offers poor resistance to oils and little resistance to the
spreading of flames, but does not emit toxic products during combustion.
Also used for HV.

Silicone rubber, which has excellent resistance to extreme temperatures

(between -80°C and + 250°C) and to external agents, giving it remarkable
aging properties.

Maximum operating
Type of insulation
temperature (°C)
Polyvinyl chloride (PVC) Conductor: 70
Cross-linked polythene and ethylene – propylene (EPR) Conductor: 90
Silicone rubber Conductor: 90

Table 4: Maximum operating temperatures for the insulations

5.3.3.3. Protective sheaths

When selecting the materials for protective sheaths, you must take the following points into
consideration:

External constraints exerted on the cable

Operating conditions, maximum temperature

Installation conditions, minimum temperature

Type of insulation used, particularly in terms of heat resistance.

The materials used are:

Insulation materials, such as those used for the insulation (see above paragraph)

Lead or lead alloys

Lead sheaths have:

• Perfect sealing

• Excellent chemical inertness

• Sensitivity to vibrations and repeated deformation

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• Poor mechanical properties which require protection in the form of an armour

or laying in conduits or in a cable tray

• Vulnerability to certain forms of electrochemical or electrolytic corrosion

5.3.3.4. The screen

The screen protects the low current circuits against disturbances produced by nearby
cables.

Individual screen (EI)

Individual screen per pair or per triplet, generally consisting of a spirally wound polyester
tape covering, the screen's continuity is provided by a tinned copper drain wire strand laid
along the cable.

General screen (EG)

Screen applied over the whole of the assembled conductors, its construction is identical to
the EI screen, however the drain can be provided by 2 or 3 copper wire strands, according
to the cable diameter.

The choice of the type of screen depends on the used of the cable in general:

• DC power supply cable: no screen

• cable for high level analogue and digital signals (4-20 mA, 24V, 48V): a general
screen (EG),

• cable for low level analogue signals, compensation cable: individual screen (EI)
+ general screen (EG)

• cables for digital signals: individual screen (EI) + general screen (EG).

5.3.3.5. Mechanical protection

Provided by an armour either consisting of:

• Two mild steel tapes, sometimes galvanised or PVC coated, spirally wound at the
joints. Disadvantage: rigidity, sensitivity to corrosion

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• One or two layers of spirally wound steel wires, generally galvanised. These
wires can have a PVC sheath.

Advantage: improved flexibility, good resistance to longitudinal forces.

Disadvantage: high price.

5.3.4. Examples of instrumentation cables

Figure 50: Instrumentation cable 01IP09EGFA

Figure 51: Instrumentation cable 12IP05EISF

Figure 52: Instrumentation cable 27IP05EIFA

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5.3.5. Summary

The following table gives the types of instrumentation cables which you are going to
encounter throughout your career as an instrument technician:

Number Number of Number of

Designation Armour
of pairs triplets quads
01 IP 09 EG FA 1 0 0 Metal tape
01 IP 09 EG SF 1 0 0 Nonarmoured
01 IQ 09 EG FA 0 0 1 Metal tape
01 IQ 09 EG SF 0 0 1 Nonarmoured
01 IT 09 EG FA 0 1 0 Metal tape
01 IT 09 EG SF 0 1 0 Nonarmoured
03 IP 05 EG SF 3 0 0 Nonarmoured
03 IP 05 EI SF 3 0 0 Nonarmoured
07 IP 05 EG SF 7 0 0 Nonarmoured
07 IP 05 EI SF 7 0 0 Nonarmoured
07 IT 05 EG SF 0 7 0 Nonarmoured
12 IP 05 EG SF 12 0 0 Nonarmoured
12 IP 05 EI SF 12 0 0 Nonarmoured
12 IT 05 EG FA 0 12 0 Metal tape
12 IT 05 EG SF 0 12 0 Nonarmoured
19 IP 05 EG FA 19 0 0 Metal tape
19 IP 05 EG SF 19 0 0 Nonarmoured
19 IP 05 EI SF 19 0 0 Nonarmoured
19 IT 05 EG SF 0 19 0 Nonarmoured
27 IP 05 EG SF 27 0 0 Nonarmoured

Table 5: Some types of instrumentation cables

As you can see, they are also available with multiconductors which range from 3 to 27
pairs and from 1 to 12 triplets. These multiconductor cables are called "multis" in
maintenance jargon.

Figure 53: Multipair instrumentation cable

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5.4. SPECIAL INSTRUMENTATION CABLES

5.4.1. Reminder of the thermocouple measuring principle

Figure 54: Thermocouple measuring principle

At the terminals of a circuit formed by two conductors (couples) of different type (e.g. iron-
constantan) an electromotive force (emf) can be measured which is directly proportional to
the temperature variation recorded in the hot zone.

The materials used depend on the temperature range to be measured. The couples are
symbolised by the letters: " J-K-S ".

To be able to move the measurement zone (cold zone) away from the hot zone we use
compensation cables: they are less expensive than thermocouple cables (markings JC –
KC – SC).

The extension cables provide the same function with a greater precision (lower
tolerance).

They are more expensive than compensation cables (markings JX – KX – SX).

A colour code is used to identify the different cables according to each country's
standards.

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5.4.2. Thermocouple compensation cables

Extension cables are used to extend the

thermocouple circuits, they take the form of an
electric cable whose conductors are made of
the same materials as those of the
thermocouple.

Compensation cables are made of other

materials (cheaper) whose thermoelectric
characteristics are identical up to 100°C

The compensation cables are defined by the

IEC 584-3 standard which, among other things,
determines the cable colour code and the
polarity

Figure 55: Various compensation cables

Practical information:

Sheath The positive conductor always has the same sheath colour.
Couple type The negative conductor is always WHITE.
colour
K green
J black
T brown Material Temp. Min. Temp. Max.
S and R orange PVC (HV) - 50 °C + 80 °C (105 °C)
Polythene - 60 °C + 70 °C
Important: any temperature Polypropylene - 40 °C + 105 °C
inversion of a compensation
Nylon - 70 °C + 120 °C
cable generates spurious
thermoelectric junctions which Polyurethane - 40 °C + 80 °C
affect the measurement Teflon FEP - 80 °C + 205 °C
precision and stability Teflon PTFE - 80 °C + 260 °C
(fluctuations linked with the
Teflon PFA - 80 °C + 260 °C
variation in ambient
temperature). Tefzel - 80 °C + 155 °C
Halar - 60 °C + 160 °C
Table 6: Temperature Silicone - 55 °C + 230 °C
resistance of the
insulations used on the Kapton - 75 °C + 260 °C
extension or Fibre glass - 70 °C + 650 °C
compensation cables Ceramic fibre 0 °C + 1430 °C

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5.4.2.1. Compensation cable codings

Couple U
Type Compensation M
Connection L
Thermocouple standard IEC C
2
3
Number of conductors 4
5
Etc.
Tc K K
Tc J J
Tc S S
Type
Tc T T
Tc B B
Copper U
Kapton K
Fibreglass silk V
PFA Fa
Conductor insulation FEP Fe
PTFE (teflon) Tf
Silicone S
PVC P
Internal screen Screened B
Kapton K
Fibreglass silk V
PFA Fa
Sheath insulation FEP Fe
PTFE (Teflon) Tf
Silicone S
PVC P
External screen Screened B
0.14
0.22
Cross-sectional
0.50
area (mm²)
0.80
(Compensation
and connection) 1.00
Wire
1.34
Etc.
0.3
Diameter (mm)
0.5
(Couple)
Etc.

Table 7: Cable codings

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5.4.2.2. Colour codings

French
Old French European German US standard
standard UK standard
standard standard standard
Conductors
ANSI MC

Symbols
NFC 42324 BS 1843
NFC 42324 IEC 584.3 DIN 43714 96.1
DE 1993
Symb

Positive Negative

K
Chromel Alumel
X

K
K Copper Constantan C
B

K
Iron Cupronickel C
A

J
J Iron Constantan
X

T
T Copper Constantan
X

S
S
o
Copper Cupronickel C
r
B
R

B
B Cupronickel Copper
C

E
E Chromel Constantan
X

N
N Nictosil Nisil
X

Table 8: Compensation cable colour coding

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5.4.3. Network cables

5.4.3.1. Profibus cable

Figure 56: PROFIBUS cable

The Profibus-DP protocol uses a high speed RS485 serial link and imposes an impedance
of 150 ohms.

Electrical characteristics:

Service voltage: 100 V

Test voltage 2,000 V

Impedance: 150 Ω+/- 10%

Capacitance: 30 pF/m

Electrical resistance: 50 Ω/km

Loop resistance: 100 Ω/km

5.4.3.2. Ethernet cable

Ethernet cable is now very often used because of the developments in PLCs and PLC
control systems which are based around industrial computer networks.

It uses two pairs of twisted wires, one pair is used to receive data signals and the other is
used to transmit data signals.

The two wires in each pair must be twisted together along the whole length of the
segment, this technique is often used to improve signal quality.

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Figure 57: Ethernet cable

RJ45 connector

This connector is derived from that used for the telephone (RJ11) but it is physically
incompatible with it (it is wider) and can contain more wires (8 compared to 6, whereas the
conventional RJ11 uses only 4 wires).

The standard pin configuration is shown here (following figure) with the standard colours. It
must be noted that the odd pins are always those with striped colours.

Colour codings
Pin Colour Pair Name
1 Orange / White 2 TxData +
2 Orange 2 TxData -
3 Green / White 3 RecvData +
4 Blue 1
5 Blue / White 1
6 Green 3 RecData -
With the connector's
clip located 7 Brown / White 4
underneath 8 Brown 4

Figure 58: The RJ45 connector and its colour code

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Straight RJ45 cable Signal Pin Pin Signal

TxData+ 1 1 TxData+
It is the most widely used model, it is
always used when connecting an TxData- 2 2 TxData-
Ethernet interface to a hub or to a RecvData + 3 3 RecvData +
switch. The pin assignments are
identical at each end of the cable: - 4 4 -

- 5 5 -

RecvData- 6 6 RecvData-
Table 9: Straight RJ45 cable - 7 7 -

- 8 8 -

Figure 59: Example of an application with a straight RJ45 cable

Figure 60: Straight cable

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RJ45 crossover cable

Used to directly connect two Ethernet interfaces together. The pin configuration at one end
is different to allow communication to take place: the transmission and reception wires are
reversed.

Signal Pin Pin Signal

TxData+ 1 1 RecvData+

TxData- 2 2 RecvData-

RecvData+ 3 3 TxData+

- 4 4

- 5 5

RecvData- 6 6 TxData-

- 7 7

- 8 8

Figure 61: Ethernet cable with RJ45 crossover connector

Figure 62: Example of an application with an RJ45 crossover cable

As you can see in this example,

using a crossover cable we can
directly connect two computers in
an Ethernet network.

Figure 63: Crossover cable

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5.4.3.3. Determining the type of RJ45 cable

Take the two ends as shown in the following

diagram and look closely at the order of the
wires:

Figure 64: Determining the type of RJ45

cable

IMPORTANT: The colour codes indicated in the previous tables correspond to a standard
but it is quite possible to find cables which use wires with completely different colours.

if the colour sequence is identical at each end: straight cable

If pins 1-2 and 3-6 are reversed: crossover cable

Neither one or the other: "unknown" cable, or at least a cable which does not
respect an Ethernet configuration.

5.4.3.4. RJ45 cable categories

Each RJ45 cable is attributed a category which defines the maximum amount of data (data
speed) speed which it can transfer without errors.

Normally, each RJ45 cable you find on the market is marked along its length with a set of
data and the cable category.

The following table gives the different categories with their current usage:

Category Maximum data speed Normal application

Voice in analogue mode (telephone)
Nominal data speed of Integrated Service
CAT 1 Less than 1 Mbps
Digital Networks (ISDN)
Doorbell wiring
CAT 2 4 Mbps Mainly used for IBM token ring
CAT 3 16 Mbps Voice and data transport for Ethernet 10baseT
Used for the high speed version of the token
CAT 4 20 Mbps ring (16 Mbps), otherwise it is not very
commonly used

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Category Maximum data speed Normal application

100 Mbps 100 Mbps (twisted pair): 100baseTX

CAT 5
1000 Mbps (4 pairs) 155 Mbps ATM Gigabit Ethernet
100 Mbps (twisted pair): 100baseTX
CAT 5E 100 Mbps
155 Mbps ATM
CAT 6 200-250 Mbps Very high data speed applications

Table 10: RJ45 cable categories

5.4.3.5. Making your RJ45 cable

The first thing you need is some category 5 cable. This can be obtained from computer or
electronics retailers, etc. You can also choose to shorten the cable supplied with the
machine.

Figure 65: Category 5 cable

The crimping tool for RJ45 connectors is more expensive. This one is relatively cheap
(around 15 euros). Near its hinge it has two blades which strip the cable, as well as a
crimping part and a cutting part.

Figure 66: Crimping tool for RJ45 connectors (1)

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I prefer to use this one, it only crimps but it does a very good job!

Figure 67: Crimping tool for RJ45 connectors (2)

You also need the RJ45 connectors and any coloured caps which may be necessary. The
caps are used to identify the different cables and protect the Ethernet connector's clip. You
obviously have to insert the cap before crimping the connector.

I would not use one on this cable because it is designed to remain in place and, because
of its length, we can immediately see what it is connected to.

Figure 68: RJ45 connectors (1)

The connectors can be different, with guides, without guides, screened. In this case these
are simple connectors.

On this side we can see the metal pins which will later fit onto the cable's wires.

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Figure 69: RJ45 connectors (2)

Personally, I don't use the stripping part

of the various tools, I prefer to use a
utility knife, and make a cut between 2
and 3 cm from the end of the cable

Figure 70: Using a utility knife

.

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In this way, I know that the conductors will

not be damaged and I have enough length to
untwist the pairs and lay them flat.

Figure 71: Untwisted cable

And the conductors are laid out flat in the correct

order:

white/orange
orange
white/green
blue
white/blue
green
white/brown
brown

Figure 72: Untwisted cable with colours in the

correct order

For a straight cable, the two ends must be placed in

this manner.

For a crossover cable, one end must be as indicated above and the other must be as
specified below:

white/green
green
white/orange
blue
white/blue
orange
white/brown
brown

The two pairs currently used (base 10 and base 100) are those which will be crossed over
(or left straight).

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After cutting the conductors straight, we slide them fully into the connector, as shown here.

Figure 73: Slide the cable into the connector

Then push the sheath as far as possible.

Figure 74: Push the sheath

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We can see that the cables are fully

inserted.

Figure 75: Cable fully home in the

connector

Figure 76: Position of the contacts and of the

plastic locking device

The yellow arrow indicates the contacts

which will be inserted onto the
conductors, the blue arrow indicates the
plastic locking device which will secure
them and their sheath in the connector.

We insert the connector carefully but

firmly into the crimping tool.

Figure 77: Inserting the connector into

the crimping tool

When the connector has been clipped into

the tool, check that the cable and sheath
are fully inserted before crimping. When it
has been crimped, repeat the operation for
the other end of the cable.

Figure 78: Connector clipped in the

crimping tool

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And our cable is now ready to use. In this example we made a 10 cm long cable but you
can make the cable any length you wish.

Figure 79: Ethernet cable

5.4.3.6. Reminder on HUBS and SWITCHES

General description:

All the data flowing in the network transits via these units. They have from 4 to 48 RJ45
ports and can thus interconnect as many Ethernet interfaces. They can also be
interconnected together via an uplink port.

This uplink port is always shared with one of the conventional RJ45 ports, which means
that you lose one port when you connect two hubs/switches together. Thus, connecting
two 8-port hubs together will result in a total of 14 ports available instead of 16.
There are two types of hubs/switches:

conventional hubs/switches (desktop/palmtop): the most commonly used models,

they are also the cheapest, and they are designed to be placed on a desk and
therefore have an attractive design. They have from 4 to 16 ports and, depending on
the model, the power supply may be internal or external.

rackable hubs/switches: they are the largest and most expensive models, they are
designed to be installed in rack units (more commonly known as cabinets). They
have from 8 to 48 ports and have an internal power supply. The recent models are
beginning to integrate gigabit Ethernet ports (1000baseTX or 1000baseFX). The top-
of-the-range models very often have a remote monitoring software suite. It must also
be noted that there are stackable models available. Their specific feature is that they
can be interconnected together (up to 8 devices depending on the models) via
special boards thus allowing very high speed transfers between all the switches
without the risk of creating bottlenecks.

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Hub operating principle

A hub retrieves the signals from a port and sends them to all the other ports. This means
that each data packet from an Ethernet interface connected to the hub is sent to all the
other interfaces present on this hub. Thus we are sure that the intended receiver of the
packet actually receives it.

The problem is that the packet is also received by all the interfaces which it is not destined
for. This generates a lot of unnecessary traffic on the network and the network becomes
more and more saturated as more and more Ethernet interfaces are added to it. Since a
hub has no means of managing the traffic it receives, the packets very often bump into
each other (collision principle).

These collisions fragment the packets and so they have to be sent again, increasing the
transfer times and therefore greatly reducing the effective speed of the network.

Switch operating principle

Whereas hubs only transfer packets over the network, switches are capable of managing
the packets they receive in different ways. Their main feature is that they can consult the
MAC address of the sender and of the receiver in each packet.

The MAC address is the unique ID number of each Ethernet interface. By keeping a trace
of these MAC addresses, a switch knows which port each Ethernet interface is located on.

Practical example

A packet arrives on port 2 with X as destination address and Y as source address. The
switch immediately knows that address Y corresponds to port 2 since the packet arrived
via this port. At the same time, a packet arrives by port 5 with Z as destination address and
X as source address. The switch now knows that address X is on port 5 and thus knows
the destination of the first packet from port 2 (with MAC address Y).

In theory this series of events happens only once for each MAC address because each
switch has an address table containing this data for future reference.

In addition to reducing the unnecessary traffic on each port, recent switches are capable of
reducing the number of collisions even further by using CSMA/CD (Carrier Sensing
Multiple Access/Collision Detection).

This feature is used among other things to check the state of the line before sending data.
If it detects that there is traffic on the line, it waits till the line is free before making the
transfer.

CSMA/CD also allows the switch to query each packet it receives and to reject those
which are fragmented or damaged, thus reducing the unnecessary traffic even more.

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Finally, a last technical point: most switches are of the "store-and-forward" type. This
means that a switch retrieves a complete packet before sending it to its destination.

The switch can therefore analyse the packet (e.g. to find out if it is a fragment resulting
from a collision) and decide if it must send it or reject it.

Store-and-forward switches must be differentiated from the cross-point models: cross-point

models start to send the packet before they have completely received it.

This gives a shorter latency time but these models are much more expensive and the
store-and-forward technologies have reached such a level of efficiency that cross-point
switches are extremely rare. All the switches available on the market are store-and-
forward switches.

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6. CONNECTING INSTRUMENTATION CABLES

6.1. CABLE GLANDS

6.1.1. Introduction

In electricity and in instrumentation a cable gland is a component which allows an electric

cable to pass through a partition, wall or bulkhead.

It provides a seal against foreign matter, dust, water, etc., and mechanically locks the
cable.

It can consist of several elements, e.g.:

A main part with dual thread forming a sleeve for the cable;

A nut which fixes the body of the cable gland to the partition, associated if
necessary with a seal,

A pressure-deformable sleeve: formerly made of tow but now made of rubber or

synthetic material and which provides the sealing;

A nut which, either by deforming the end of the cable gland body, or using a
cylindrical or tapered wedge, applies pressure to the deformable sleeve.

The cable passes through all the parts, in other words the cable gland is assembled by
sliding the different elements onto the cable.

A cable gland can be made of metal (usually brass), or

synthetic material (plastic).

Figure 80: Example of a standard plastic cable gland

A metal cable gland can, where necessary, be

used to earth the cable screen (triple effect
cable gland).

Figure 81: Standard metal cable gland

It is important to use the right type of cable gland according to the protection zones
defined by the ATEX 95 standard.

The standard size of an instrumentation cable gland is M20 x 1.5.

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It is important to ensure that the diameter of your cable gland correctly corresponds
to your cable diameter because, on site, I once saw a large cable gland with a small
cable and the whole assembly had been sprayed with silicone.

6.1.2. Procedure for electrically connecting a transmitter

Follow the instructions given below for wiring the transmitter:

1. Remove the plastic protection blanks, from one or both the electrical connections
present on the sides of the top part of the transmitter housing.

2. Remove the cover from the housing on the connection side. For explosion-proof
installations (certified Eex d), do not open the transmitter covers when the
transmitter power supply voltage is present.

3. If an output indicator is present, remove it by unclipping it. Apply a strong pressure

to the whole of the indicator to prevent the cover from coming away from its base.

4. Slide the cable into the cable gland and into the open access.

5. Connect the positive conductor to the + terminal and the negative conductor to the
- terminal.

Figure 82: Electrically connecting the transmitter

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6. Tighten the cable gland and seal the electrical accesses. When the installation
procedure is terminated, ensure that the electrical accesses are correctly sealed
against the ingress of rain, gas or corrosive vapours.

7. If possible, install the wiring with a ‘drip loop’, where the bottom of the loop is
below the conduit connection and the transmitter housing.

Figure 83: Drip loop on a transmitter

8. Screw up the housing cover by turning it until there is metal to metal contact
between the cover and the transmitter housing. For explosion-proof installations
EEx d or i, lock the cover by turning the locking screw.

9. And that is all!! Your transmitter is now wired according to good instrumentation
practices.

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6.2. CONNECTING A CABLE TO A COMPRESSION COUPLING

Mark the place where the cable armour must be cut.

Cut away the PVC sheath with a knife.

Expose (uncover) the armour.

Tie a piece of wire around the armour.

Leave a space for the cable gland between the wire

and the end of the PVC sheath.

Cut part of the way through the armour wire with a

hacksaw.

If you cut all the way through the armour you may
damage the inner core insulation.

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Cut the armour wires with a hacksaw.

The wires must be cut evenly.

Take only four (4) or five (5) strands at any one time.

Cut back a little more of the outer sheath so enough

of the armour is showing to cover the end of the
clamping cone.

Now you can see the insulation around the inner

core.

Place the gland locking nut and the compression ring

over the cable.

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Twist the inner core against the lay of the steel wire
armour. (depends on which end of the cable you are
removing).

The steel wire will fan out.

Place the main body of the cable gland over the

inner core.

Make sure the steel wire goes over the top of the
gland.

Move the compression ring over the steel wire.

Make sure the wire is gripped between the

compression ring and the gland.

Move the locking nut over the compression ring and

tighten it on to the gland.

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Remove the inner PVC sheath to expose the

conductors.

Remove the insulation from the end of each

conductor so the conductors can be terminated.

Mark the place where the cable armour must be cut

Cut away the PVC sheath with a knife.

Expose (uncover) the armour.

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Tie a piece of wire around the armour.

Leave a space for the gland between the wire and

the end of the PVC sheath.

Cut part way through the armour wire with a

hacksaw.

If you cut all the way through the armour you may
damage the inner core insulation.

Break off armour wires.

The wires must break off evenly.

Take only four (4) or five (5) strands at any one time.

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Cut back a little more of the outer sheath so enough

of the armour is showing to cover the end of the
clamping cone.

Now you can see the insulation around the inner

core

Place the gland locking nut and the compression ring

over the cable

Twist the inner core against the lay of the steel wire
armour. (Depends on which end off the cable you
are making off).

The steel wire will fan out.

Place the main body of the gland over the inner core.

Make sure the steel wire goes over the top of the
gland.

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Move the compression ring over the steel wire.

Make sure the wire is gripped between the

compression ring and the gland.

Move the locking nut over the compression ring and

tighten it on to the gland.

Remove the inner PVC sheath to expose the

conductors

Remove the insulation from the end of each

conductor so the conductors can be terminated

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Figure 84: Cable gland with compression coupling

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7. CABLE BRACKET - CABLE TRAY

7.1. GENERAL

You must start by differentiating the cable trays, each level of voltage has an assigned
cable tray, each electrical field (and related fields) has a specific cable tray or a specific
portion of cable tray.

Each specific use or discipline has its own specific cables for technical reasons
(interference, safety, etc.). There must be independent routings for each type of cable.

The different cable trays on a site are designed for:

High voltage

LV power circuits

LV control circuits

Control instrumentation (4-20mA, etc.)

Low current instrumentation (thermocouples, etc.)

Distribution bus instrumentation

Telephony

IT

The earth of the equipment grounds (where applicable)

etc.

All these cables and circuits are routed and cross over each other according to
predetermined rules.

Therefore, when on site, please do not ask to add a cable to power your computer or
control room TV by running your cable along a lightning conductor drop stack, for example,
claiming that it is more convenient. (There is a good reason for this… ask your instructor
for an explanation if you do not understand why).

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You may get a few surprises: "why

does the compressor cut out when
we start the transfer pump?" If the
vibration sensor cable or
thermocouple cables pass close to
the pump's 6 kV cable, it is not
surprising. (Other phenomena may
very well not give any indication of
what triggers the fault in the case of
rapid transient induction.)

Cable trays are made of different

materials (galvanised steel, stainless
steel, fibre glass, PVC, etc.),
different constructions (wire, ladder,
perforated, etc.) and a wide range of
colours, etc. Troughs, conduits and
tubes (steel or PVC) are all similar to
cable trays since they support/guide
wires or cables.

Figure 85: Different types of cable

trays

In addition to providing mechanical protection, the covers of cable trays are mainly used
to protect cables from the aggression of UV which damages the outer insulation sheath
over time.

7.2. LAYING CABLES

The following tips concern aligning cables on cable trays.

Figure 86: Horizontal distances between cable trays

Whether the cable trays are laid vertically or horizontally, a minimum installation
distance must be maintained between the different types of cable trays.

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A distance of 200 mm is frequently used. However, check

the correct specifications, as this may not be the case.

Cable trays are mechanically and electronically splinted

together using a ground conductor connected to the
general earth. This includes PVC and fibre glass cable
trays (static electricity!)

Figure 87: Distances between cable trays when installed

vertically

Trefoil (clover leaf) or aligned configurations

This concerns power cables. The conductors of a cable carrying three phase current are
manufactured twisted together to cancel (or rather to minimise) the electromagnetic
induction produced by each phase (imagine the 3 vectors at 120°, their vector component
is zero).

Figure 88: Trefoil or aligned configurations

Three-phase cables (or three + N) may be laid either aligned or in a trefoil configuration.
However, for high powers, when several single-pole cables form one phase, the trefoil
technique must be used, the 3 conductors in the trefoil represent the 3 phases.

As a general rule, the cables must not be just "thrown" on the cable trays but aligned and
attached. This is not just because it looks better but is also for maintenance purposes (it is
easier to add/remove a cable) and to reduce the induction phenomena.

If you find cables which are heating up, or even a hot cable tray, this is not necessarily due
to a current overload, it may simply be because the cables are incorrectly laid…

7.3. LADDER RACK

Ladder rack (also known as "cable ladder" or "ladder cable tray")is a quick and easy
method of transporting heavy-duty cables over long distances and in the worst site
conditions since it can withstand high winds, heavy snow, sand or dust buildup, or high
humidity.

The ladder is very strong and can be mounted in virtually any direction.
Ladder rack is made of hot dipped galvanised steel.

It can often be used in conjunction with a cable tray on an installation.

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Figure 89: Ladder rack

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You can find ladder rack supports on site in switchgear/MCC electrical rooms and they are
even very often found in the basement of those rooms.

Ladder rack accessories

90° Bend 90° Outside Upright Equal Tee

Straight Reducer 90° Inside Upright Equal Crossover

Horizontal Hinged Coupler Flat Coupler Vertical Coupler

Table 11: Ladder rack accessories

7.4. THE DIFFERENT TYPES OF CABLE TRAYS

7.4.1. Types of cable trays available

Ladder Channel

Solid bottom Wire mesh

Trough Single rail

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7.4.1.1. Ladder cable trays

Ladder cable trays provide:

A solid side rail protection and good

system strength with smooth radius
fittings and a wide selection of
materials and finishes

Figure 90: Ladder cable trays

.
Maximum strength for long span applications with standard widths.

Standard depths

Standard lengths.

Rung spacing.

Standard dimensions depend on the countries and the manufacturers.

7.4.1.2. Solid bottom cable trays

Solid bottom cable trays provide:

Nonventilated continuous support for more

fragile cables and an added protection for the
cables made of metal or fibreglass.

Solid metal bottom with solid metal covers for

cables installed in overhead zones.

Standard widths

Standard depths

Standard lengths

Figure 91: Solid bottom cable tray

Standard dimensions depend on the countries and the manufacturers.

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Solid bottom cable trays are generally used for electrical or telecommunication
applications generating minimal heat and for computer applications with short to
intermediate support spans.

This type of tray is not recommended for use on sites due to the lack of ventilation
afforded.

7.4.1.3. Trough cable trays

Trough cable trays provide:

Moderate ventilation with added cable

support frequency and the
configuration of the bottom part allows
cable supports/tying at very short
distances. Available in metal and
nonmetal materials.

Figure 92: Trough cable trays

Standard widths

Standard depths

Standard lengths

Fixed rung spacing at the centre

Figure 93: Perforated cable trays

Standard dimensions depend on the countries and the manufacturers.

Trough cable trays are generally used for applications generating moderate heat with short
to intermediate support spans of 1.5 to 3 m.

The perforated cable tray is also a type of trough cable tray.

7.4.1.4. Channel cable trays

Channel cable trays provide:

Cost-effective support for cable drops and branch cable runs from the backbone
cable tray system.

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Standard widths in metal and

nonmetal systems.

Standard depths in metal systems

and 1 depth in a nonmetal system

Standard lengths.

Figure 94: Channel Cable Tray

Standard dimensions depend on the countries and the manufacturers.

Channel cable trays are used for installations with limited numbers of cable in the tray
when conduit is undesirable.

Support frequency with short to medium support spans of 1.5 to 3 m.

7.4.1.5. Wire mesh cable trays

Wire mesh cable trays provide:

A field-adaptable job site support system primarily

for low voltage, telecommunications and fibre
optic cables. These systems are normally made
of zinc plated steel wire mesh.

Figure 95: Wire mesh cable trays

Standard widths

Standard depths

Standard lengths

Standard dimensions depend on the countries and the manufacturers.

Wire mesh trays are generally used for telecommunications and fibre optic applications
and are installed on short support spans of 1 to 2 m.

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7.4.1.6. Single rail cable trays

These aluminium systems (other materials are now

used) are the fastest systems to install and provide
maximum freedom for the cable to enter and exit the
system.

Single-hung or wall mounted systems in single or

multiple tiers.

Figure 96: Single rail cable trays

Standard widths

Standard depths

Standard lengths

Standard dimensions depend on the countries and the manufacturers.

Single rail cable trays are generally used for low voltage and power cable installations
where maximum cable freedom, side fill and fast installation are important factors.

7.4.2. Materials / finishes available for the various cable tray systems

Steel (Min. Yield = 33KSI) (35 KSI for stainless steel)

Solid: hot rolled pickled and oiled steel as per ASTM A569 (Commercial
Quality) or A570 (Structural Quality).

Pregalvanised: galvanised milled steel as per ASTM A653 CS (Commercial)

or SS (Structural Quality) G90

Hot dip galvanised after fabrication: black steel which is hot dipped after
fabrication as per ASTM A123.

Stainless steel: type 304 or 316L fully annealed stainless steel.

Aluminium (Min. Yield = 23 KSI)

Alloy 6063-T6 or 5052-H32 as per ASTM B209.

Fibre-Reinforced Plastic (FRP)

Polyester and Vinyl Ester resin systems available.

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Meets ASTM E-84 smoke density rating; Polyester 680, Vinyl Ester 1025.

Class 1 flame rating and self-extinguishing requirements of ASTM D-635.

7.4.3. Cable tray mounting accessories

It is impossible to show all the items which could be used for the different types of cable
trays, it would require a 200-page catalogue.

Here are some examples.

Accessories for cable trays

Equal Tee 90° Outside Riser Straight Reducer

Equal Crossover 90° Inside Riser External Wrap-over Coupler

90° Bend Internal Short Coupler

Table 12: Accessories for cable trays

When these accessories are unavailable, the following methods are recommended for the
construction of various bends and junctions. It should be noted that all cuts in the metal
should be painted with a rustproof paint.

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7.4.4. How to construct a flat 90° bend

The first step is to mark out the tray

(A).

Figure 97: Construction of a flat 90°

bend (A)

The amount of tray lip to be removed

is equal to 2, 3/4 the width of the tray,
half of this measurement will be
removed on either side of the centre line.

To remove the lip we can use a small hand grinder (B) or a file (C), but care must be taken
when using a hand grinder to ensure that the protective equipment is in good condition.

Figure 98: Construction of a flat 90° bend

(B)

Figure 99: Construction of a flat 90° bend (C)

Next we cut down the centre line,

care must be taken not to let the
tray fall open at this point as it may
be damaged (D).

Figure 100: Construction of a flat

90° bend (D)

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Now use a blunt object to flatten the tray

lip at the point where the tray will be
bent (E).

Figure 101: Construction of a flat 90°

bend (E)

Then bend the tray to 90° and bolt the two parts
together (F)

Figure 102: Construction of a flat 90° bend (F)

Now we measure the distance between the 2

internal edges (G).

This will be the measurement for our gusset.

Figure 103: Construction of a flat 90° bend (G)

The gusset is produced by cutting a piece of tray

to the required size, removing 1 lip completely
and bolting it to the 90° bend (H).

Figure 104: Construction of a flat 90° bend (H)

This completes the 90° bend.

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7.4.5. How to construct a Tee piece

The first step is to mark and remove the tray lip (1).

This measurement is equal to twice the width of the

tray.

We also remove one and a half times the width of

the tray from the piece of tray to be added to the
Tee.

Figure 105: Construction of a Tee piece (A)

The 2 pieces of tray are now bolted together (2).

Figure 106: Construction of a Tee piece (2)

Next we measure the gussets (3)

Figure 107: Construction of a Tee piece (3)

Once the gussets have been made, the

final step is to bolt the tray together and
produce a Tee piece (4).

Figure 108: Construction of a Tee piece (4)

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7.4.6. How to construct a 90° external bend

This is perhaps the easiest bend to make. We first mark out the tray (a).

The lines are drawn 75 mm apart, we cut down all 3 lines on both sides of the tray and
bend to 90° as shown in figures (b) and (c).

Figure 109: Construction of a 90° external bend

To make bending the tray easier, try using a round object such as a scaffold tube,
handrail, etc.

7.4.7. How to construct a 90° internal bend

We first mark and remove the tray lip (1). The lines are drawn 75 mm apart. Next we
measure 12 mm on either side of each of these 3 lines, draw 2 diagonal lines from point A
to B and point A to C on all the lines and on both edges of the tray and remove them. Then
bend to 90° (2).

Figure 110: Construction of a 90° internal bend

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7.4.8. How to construct an offset

First mark the tray (11), draw a centre line, measure 10 mm approx. on either side of the
centre line and draw 2 lines.

Now draw 2 diagonal lines from point A to point B and from point A to point C and remove
as shown in figure (12).

Figure 111: Construction of an offset (11) and (12)

Then bend the tray and measure the size of the required offset (13)

Figure 112: Construction of an offset (13) and (14)

Once the size of the offset has been determined, mark out the cut on both edges, then
bend to the required shape (14).

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When the bends and offsets have been completed, all cuts must be painted with a
rustproof/corrosion-proof paint.

Those “operations” were carried out on a perforated galvanised steel cable tray, the
procedure would be almost identical with a stainless steel or fibre cable tray.

7.4.9. Earthing the cable trays

Whatever the type of metal cable tray, it must be earthed:

To the plant's general earthing system every 15 to 20 m.

To the plant's general earthing system at its ends if the length is less than 15 m.

All along the earthing wire connected with specific studs to ensure electrical
continuity between the lengths. (as shown in the figure)

Figure 113: Earthing a cable tray

Also see the Company Standards

on this point.

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8. LOW VOLTAGE CABLES

Electricity flows from the supply to the load through cables. Cables are an integral part of
all circuits. Every cable has to be connected to some part of the circuit.

The connection of a cable to any part of the circuit is called a termination. There are many
different types of terminations for different conditions and equipment.

The aim here is not to develop the complete technology of terminations inside cubicles,
panels and junction boxes, but only to show the accessories such as lugs, terminals and
tools to use, etc. If a termination is not made correctly it can cause a lot of problems. A bad
termination may overheat and start a fire. A connection may have a very high resistance
which can cause problems with the power supply to the equipment.

For the “other accessories”, i.e. the cable glands, the cable trays, the wall crossings, and
the different cable laying devices, see next chapter. This present paragraph covers the
most common types of cable terminations.

Cable terminations are an important part of the electrician's job. Therefore they must be
made correctly using the right tools and equipment.

8.1. CABLE TERMINATIONS

The connection of a cable inside

a device or piece of equipment is
called a termination. All electrical
terminations must be both
electrically and mechanically
secure.

Figure 114: Cable termination.

The termination must be good

enough to carry the load current
of the circuit.

This means that the connections

must have a low resistance and
the cable must be tightly secured.

There should be no mechanical strain on the conductor connections.

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The cable should be held firmly in the termination enclosure by a cable grip. Any
mechanical strain should be on the cable grip, not on the conductors.

Different types of cable grips guarantee the level of mechanical strain exerted on the
termination.

Here are some special

cable glands, collars and
tension reducers adapted
to different types of
cables and termination
enclosures.

Figure 115: Types of

cable grips used on small
household appliances.

If the conductors in the termination are under mechanical strain then they may become
loose. A loose connection could overheat and cause a fire or it could disconnect and break
the circuit.

It is important that all terminations meet the following conditions:

A termination should be electrically and mechanically secure.

The cable sheath should be intact and undamaged right up to the termination
enclosure.

Figure 116: Terminal connections

There should be little or no mechanical strain on the termination conductor

connections.

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The insulation should be intact and undamaged right up to the terminals

All the conductor's strands must be intact and securely held in the termination. No
loose wires.

8.2. REMOVING THE INSULATION

Before a conductor can be terminated, the cable insulation must be removed. Removing
the sheath and insulation from a cable is called stripping the cable. Cable stripping can be
done using side cutting pliers or a stripping knife.

8.2.1. Removing the sheath using side cutting pliers

1. Split the sheath along the length of the cable. Be careful not to damage the insulation of
the wires.

2. Peel back the sheath and cut away the unwanted portion. (See figure 14-4).

Figure 117: Cut away the unwanted portion of the sheath

3. Check the conductor insulation for damage.

4. Where there are two or three layers of protection, they

must be removed separately.

Figure 118: Remove each layer of protection separately.

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8.2.2. Stripping insulated wires with a stripping knife

The insulation around a wire (conductor) can be stripped with a stripping knife.

A stripping knife should have a short, wide

blade with a flat end.

Figure 119: Typical electrician's stripping knife

It is important to hold the knife at an acute

angle when cutting the insulation.

Make two or three cuts from different

sides of the wire. Then pull off the
unwanted insulation with a pair of pliers.

Figure 120: Cutting the insulation with a

knife

Do not cut into the conductor

A conductor with a nick (small cut) in it

is doubly dangerous.

1. It will break after it has been bent a

few times.

2. The cross-sectional area will be

smaller so the resistance in that part of
the conductor will be higher. This can
cause overheating.

Use wire strippers to strip wire where possible. They do a cleaner, better job.

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8.2.3. Wire stripping tools

You can use a special kind of pliers to remove the insulation from a wire. The jaws have V-
shaped notches. When the jaws are closed the notches form a hole. You can adjust the
jaws so that they only cut the insulation. When correctly adjusted they do not cut the wire.

Figure 121: Adjustable wire stripping pliers

How to use wire strippers.

1. Turn the adjusting screw so that the grip in the jaws corresponds to the right wire
diameter.

2. Tighten the lock nut.

3. Place the wire in the V of the bottom jaw and close the pliers on the wire (Part (A) in the
figure).

4. Turn the pliers and pull the wire out of the jaws to remove the insulation (Part (B) in the
figure).

Figure 122: Using wire strippers

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There are other kinds of wire stripping tools which work on the same principle. When the
jaws close they form a hole so that they only cut the insulation. They leave the wire intact.

See the “Automatic stripping pliers” pictures. Some tools even combine the stripping and
crimping functions, but only for small wire cross-sections.

Figure 123: Set of automatic stripping (stripping and crimping) pliers

After the insulation has

been removed, check
that the conductor has
not been damaged.

Figure 124: Check the

state of the conductors

A conductor which has been damaged will break easily or it will increase the resistance in
the wire. So you must be careful not to damage the conductor when removing the
insulation.

If the cable has a stranded conductor then the

strands should be twisted together tightly
before making the termination. Use pliers (flat
nose pliers preferably) to twist the strands in
the direction of the existing twist (lay) of the
cable.

Figure 125: Preparing a stranded cable

You must make sure that all the strands are

fitted into the termination.

If not, the current carrying capacity of the cable will be reduced. Also, loose strands in the
termination can cause short circuits.

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8.3. TYPES OF TERMINATIONS AND CONNECTIONS

There are many different ways of joining or terminating conductors. The different methods
of termination are divided into two groups:

Heated terminations (e.g. brazing, soldering)

Mechanical terminations (clamping, bolting, etc.)

This paragraph will cover mechanical terminations only.

8.3.1. Mechanical terminations

The advantage of mechanical terminations is that they are strong but the connection is not
permanent. It can therefore be taken apart easily for repairs or changes to the circuit.

The disadvantages are that the terminals can oxidise and screwed joints can become
loose over a period of time (This is why you need regular maintenance operations to
retighten the connections).

The most common types of mechanical terminations are:

Pillar Terminals

Screw Terminals

Nut and Bolt Terminals

Strip Connectors

Claw washers

Split bolt connectors

8.3.1.1. Pillar terminals

You often see pillar terminals in the plugs on

household appliances.

Figure 126: Pillar Terminal

A pillar terminal has a hole through the side where

you insert the conductor. A set screw is tightened
onto the conductor.

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If the conductor is small in relation to the hole, it should be doubled back.

You can put two or more conductors in the same terminal by twisting them together.

You must be careful not to

damage the conductor by
tightening the set screw too
much.

Figure 127: Overtightened

set screw

8.3.1.2. Screw terminals and nut-bolt terminals

When fastening conductors under screw heads or nuts the conductor should be formed
into a loop. You can do this easily using round-nosed pliers.

Figure 128: Screw terminal and nut-bolt terminals

The loop should be placed so that when you tighten the screw or nut you do not cause the
loop to open.

Figure 129: Round nosed – half nosed – long and short nosed pliers

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8.3.1.3. Claw washers (also know as toothed washers)

You can use a claw washer to

prevent the loop from opening when
you tighten the screw.

Figure 130: Claw washer

Place the plain washer on top of the

loop. Then place both the loop and
the plain washer on the claw washer.
Tighten until the metal teeth of the
claw washer are flat on the terminal loop.

8.3.1.4. Strip connectors

Strip connectors are sometimes called terminal blocks.

Strip connectors are a group of brass connectors fitted in
a line in a moulded insulated block.

Figure 131: Strip connectors in moulded blocks

The conductors are held in place with a grub screw in

the same way that a set screw grips the conductor on
a pillar terminal.

The conductors should be pushed well into the

connector.

Figure 132: Connections on a strip connector

This prevents the grub screw only gripping the end of the conductor.

It is important to get a good, clean, tight connection.

This will prevent high resistance contacts which

would cause the connection to overheat.

It will also prevent loose contacts which might come

apart.

Figure 133: Inserting a conductor into a terminal

block

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Some connectors have pressure plates which produce better connections.

Figure 134: Pressure plate terminal block

A pressure plate spreads the pressure over the

connection and provides a better contact between
the two conductors.

This is especially important when you are dealing with high current circuits. They are also
good for multistrand conductor terminations.

Grub screw or pressure plate

terminals are normally used for
terminations in electrical
equipment, e.g. switchgear,
starters, breakers, contactors, etc.

Figure 135: Standard terminals for

switchgear

8.3.1.5. Split-bolt connectors

Split-bolt connectors are used to join two or more cable ends together. They are also
called line tap connectors. This is because they are often used to tap off a conductor (line)
without switching off the circuit.

Figure 136: Split-bolt connector

8.3.2.

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8.3.3. Crimped connections

Crimping is a quick and effective way of joining different types of termination devices to
cable conductors.

Do not crimp a rigid core cable since it can be directly connected to the terminal block
without any problems; it is even recommended never to use lugs on rigid cores!

But when dealing with stranded cores or even flexible wires it is a professional error not to
use crimped terminations when the receiver's connectors are not adapted to the wires.

8.3.3.1. Crimped lugs

Figure 137: Types of crimped terminations (small wire sizes)

Crimping requires the use of a special tool (crimping tool) to apply enough pressure to
form a good connection between the crimp connector and the conductor.

A correctly crimped connection

has high mechanical strength and
good electrical conductivity.

Figure 138: Crimped connection

Crimped connections are quicker to make and cheaper than soldered connections.
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Crimped connections are often used for small cables and made by a hand-operated
crimping tool.

But before crimping, you need to choose a lug or a sleeve and these depend on:

Wire material: copper or aluminium – It can be also bimetal, crimped on

aluminium cable and connected to a copper-based bolt/seat.

Wire size: from 0.5 to 600 mm²

Type of connection: pin, fork, blade, spade, ring, etc.

Figure 139: Table of crimp lugs / sleeves

With so many different sizes and types you are obviously not going to be able to use the
same crimping method or the same crimping tool for all of them!

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8.3.3.2. Crimping tools

Hand crimping tools often have jaws which can be changed to fit the different shapes and
sizes of crimp connectors. You crimp the connection by squeezing the handles together.

The handles cannot be released until full pressure is applied to the connection (except for
the “fastener” type crimping tool).

Then the ratchet releases the handles. This ensures that the correct pressure is applied to
the crimp connection.

A power-operated crimping tool (hydraulic) is used for crimping the large conductors of
high current cables.

Figure 140: Hand-operated crimping tool

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Figure 141: Hydraulic hand-operated crimping tool

With this type of tool for making a compression crimp, the correct die must be used
(depends on lug/sleeve diameter).

The hydraulic crimping tool can be hand-operated, battery-operated or have a separate

pump which can also be manually, pneumatically or electrically operated.

Figure 142: Hydraulically-operated crimping tool kit (hand-operated, battery, hand pump)

8.3.4. Making a crimped connection

1. Strip the insulation from the end of the stranded conductor.

Figure 143: Remove the insulation from the wire

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This systematically applies for stranded and flexible cable

2. Twist the strands together with pliers so they all fit into the body of the crimp connector.

3. Place the barrel of the crimp connector over the conductor

Figure 144: Place the device on the conductor

4. Place the barrel of the crimp connector in the

crimping tool jaws.

Figure 145: Place the connector in the crimping tool

5. Crimp the connection by squeezing the handles of the crimping tool, or start to pump
.

Figure 146: Making a crimp connection.

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6. Squeeze the handles together until the ratchet releases them (the die is completely
closed or the punch is at its maximum with the hydraulic unit).

Open the handles and remove the tool

from the crimped connection.

Figure 147: Released Crimping Tool

7. Check that the connections are well-formed and perfectly made.

The wire has been stripped to the

correct length corresponding to
portion ‘B’.

The insulation is well inside its

barrel.

The finished crimp is firmly

secured.

Figure 148: Summary of the

crimping procedure

8.3.5. Use the correct crimping method

With a hand crimping tool for small lugs, it is a simple operation.

Once you have to use hydraulic equipment, it means that you have to connect cables of
large cross-sectional areas and you must:

Decide on the compression method and dies to be used.

o Select the correct shape of die for the job.

o Select the size of die for the diameter of the lug.

o Ensure that the correct hydraulic pressure is used (check the manufacturer's
recommendations).

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Diagram Designation Applications Size

Crimping ”normal design” Cu tubular cable lugs and

Hexagonal
connector tubular cable lugs for connections in 6 to 1,000 mm2
crimp
switchgear.

Crimping ”normal design” Cu tubular cable lugs and

Mandrel shaped
connectors tubular cable lugs for connections in 0.75 to 400 mm²
crimp
switchgear.

Crimping double crimp cable lugs, C clamps, insulated

Oval crimp tubular cable lugs and connectors, insulated pin cable 0.1 to 185 mm²
lugs.

Trapezoidal
Crimping sleeves with lug and twin sleeves lug. 0.14 to 185 mm²
crimp

Square crimp Crimping sleeves with lug and twin sleeves lug. 0.14 to 6 mm²

WM crimp Crimping ”standard” tube terminals. 10 to 400 mm²

10 sm to 300 sm
Rounding Crimping 90° and 120° sector wires
35 se to 300 se

Cutting dies

Table 13: Choice of dies for a crimping tool

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Decide on the punching method to be used (bottom die)

Figure 149: Bottom-die crimping tool with separate hydraulic pump

o Slide the lug bed and punch the cover over a certain diameter only

o Change the bed and punch according to the lug diameter if your tool can
handle it.

o Check the manufacturer's recommendations for the number of punches on

the selected lug.

Position the lug correctly

Figure 150: Wrong positions of wire on lugs

Figure 151: Correct positions of wire on lugs

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This lug position is (of course) valid for all types of lugs and sleeves.

With a preinsulated compression

lug, do not forget to insert the
wire's insulation into the part of
the lug designed for this purpose.

Figure 152: Preinsulated straight

copper terminal lug.

Crimp the cable lug or connector using the correct tool, take account of the
crimping direction (when several crimps are required).

Figure 153: Crimp in correct direction

Discard any “failed” crimps

Figure 154: Crimping problems…

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This kind of problem (lug cracking) can occur either due to a material failure
(manufacturer's responsibility) or to a wrongly used crimping tool (wrong die,
excessive pressure).

Make at least a double crimp (large lugs)

The recommended method is to double crimp although single crimps may be

suitable for smaller cables.

The crimps should be at 90° to each other and positioned centrally within the contact
zone to be crimped, as shown in the figure (in this case: hexagonal die).

If a single crimp is used, the crimp should be positioned centrally within the 35 mm zone
shown in the figure.

Crimp in the order shown to ensure a satisfactory crimp is obtained. Consult the workshop
manual/manufacturer's manual if any additional information or advice is required.

Figure 155: Double crimp recommendation for standard die dimensions

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9. FIGURES
Figure 1: 2-way manifold......................................................................................................7
Figure 2: 3-way manifold......................................................................................................8
Figure 3: 5-way manifold......................................................................................................8
Figure 4: 3-way manifold associated with a transmitter .......................................................8
Figure 5: Wall mounting bracket for a transmitter ................................................................9
Figure 6: Mounting bracket for 2" tube for a transmitter.....................................................10
Figure 7: Mounting the transmitter on the mounting bracket..............................................10
Figure 8: BSP threads........................................................................................................11
Figure 9: Metric threads .....................................................................................................12
Figure 10: NPT threads......................................................................................................12
Figure 11: Definition of the thread......................................................................................13
Figure 12: Circular dies......................................................................................................13
Figure 13: Die stock ...........................................................................................................14
Figure 14: Making a thread ................................................................................................15
Figure 15 : Nuts and rings..................................................................................................15
Figure 16: Male union ........................................................................................................16
Figure 17: Female union ....................................................................................................16
Figure 18: Male end fitting for tube ....................................................................................16
Figure 19: Equal union fitting .............................................................................................17
Figure 20: Piping penetration.............................................................................................17
Figure 21: 45° elbow coupling............................................................................................17
Figure 22: 90° union elbow ................................................................................................17
Figure 23: 90° male elbow coupling...................................................................................18
Figure 24: 90° female elbow coupling................................................................................18
Figure 25: Union Tee .........................................................................................................18
Figure 26: Male Tee...........................................................................................................18
Figure 27: Female Tee.......................................................................................................18
Figure 28: Straight quick-connect coupling ........................................................................19
Figure 29: 90° elbow quick-connect coupling.....................................................................19
Figure 30: 45° elbow quick-connect coupling.....................................................................20
Figure 31: Quick-connect tees ...........................................................................................20
Figure 32: Tube precrimping tool .......................................................................................21
Figure 33: Insertion of the tube in the precrimping tool ......................................................21
Figure 34: Crimping the tube in the tool .............................................................................21
Figure 35: Insertion of the crimped tube into a coupling ....................................................22
Figure 36: Application of Teflon (PTFE) on all couplings ...................................................23
Figure 37: "Loctite" for sealing the couplings .....................................................................23
Figure 38: Diagram of NPT coupling with internal and external threads ............................26
Figure 39: Polyamide tube .................................................................................................26
Figure 40: Construction of a ‘standard’ cable.....................................................................28
Figure 41: Cu conductor/Al conductor ...............................................................................28
Figure 42: Different cable sheaths (mechanical protection) ...............................................31
Figure 43: Different PVC sheaths ......................................................................................32
Figure 44: Steel wire armoured (SWA) cable.....................................................................32
Figure 45: Cross section of high temperature resistant cables ..........................................33

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Figure 46: Construction of a mineral-insulated cable .........................................................33

Figure 47: Conventional cable U1000 R2V........................................................................34
Figure 48: Cable HO7 RN-F ..............................................................................................36
Figure 49: Exploded view of an instrumentation cable.......................................................39
Figure 50: Instrumentation cable 01IP09EGFA .................................................................44
Figure 51: Instrumentation cable 12IP05EISF ...................................................................44
Figure 52: Instrumentation cable 27IP05EIFA ...................................................................44
Figure 53: Multipair instrumentation cable .........................................................................45
Figure 54: Thermocouple measuring principle...................................................................46
Figure 55: Various compensation cables ...........................................................................47
Figure 56: PROFIBUS cable..............................................................................................50
Figure 57: Ethernet cable...................................................................................................51
Figure 58: The RJ45 connector and its colour code ..........................................................51
Figure 59: Example of an application with a straight RJ45 cable.......................................52
Figure 60: Straight cable....................................................................................................52
Figure 61: Ethernet cable with RJ45 crossover connector.................................................53
Figure 62: Example of an application with an RJ45 crossover cable ................................53
Figure 63: Crossover cable................................................................................................53
Figure 64: Determining the type of RJ45 cable..................................................................54
Figure 65: Category 5 cable...............................................................................................55
Figure 66: Crimping tool for RJ45 connectors (1) ..............................................................55
Figure 67: Crimping tool for RJ45 connectors (2) ..............................................................56
Figure 68: RJ45 connectors (1) .........................................................................................56
Figure 69: RJ45 connectors (2) .........................................................................................57
Figure 70: Using a utility knife............................................................................................57
Figure 71: Untwisted cable ................................................................................................58
Figure 72: Untwisted cable with colours in the correct order..............................................58
Figure 73: Slide the cable into the connector.....................................................................59
Figure 74: Push the sheath................................................................................................59
Figure 75: Cable fully home in the connector.....................................................................60
Figure 76: Position of the contacts and of the plastic locking device .................................60
Figure 77: Inserting the connector into the crimping tool ...................................................60
Figure 78: Connector clipped in the crimping tool..............................................................60
Figure 79: Ethernet cable...................................................................................................61
Figure 80: Example of a standard plastic cable gland .......................................................64
Figure 81: Standard metal cable gland ..............................................................................64
Figure 82: Electrically connecting the transmitter ..............................................................65
Figure 83: Drip loop on a transmitter .................................................................................66
Figure 84: Cable gland with compression coupling............................................................74
Figure 85: Different types of cable trays ............................................................................76
Figure 86: Horizontal distances between cable trays.........................................................76
Figure 87: Distances between cable trays when installed vertically...................................77
Figure 88: Trefoil or aligned configurations........................................................................77
Figure 89: Ladder rack.......................................................................................................78
Figure 90: Ladder cable trays ............................................................................................80
Figure 91: Solid bottom cable tray .....................................................................................80
Figure 92: Trough cable trays ............................................................................................81
Figure 93: Perforated cable trays.......................................................................................81

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Figure 94: Channel Cable Tray..........................................................................................82

Figure 95: Wire mesh cable trays ......................................................................................82
Figure 96: Single rail cable trays........................................................................................83
Figure 97: Construction of a flat 90° bend (A)....................................................................85
Figure 98: Construction of a flat 90° bend (B)....................................................................85
Figure 99: Construction of a flat 90° bend (C)....................................................................85
Figure 100: Construction of a flat 90° bend (D)..................................................................85
Figure 101: Construction of a flat 90° bend (E)..................................................................86
Figure 102: Construction of a flat 90° bend (F) ..................................................................86
Figure 103: Construction of a flat 90° bend (G) .................................................................86
Figure 104: Construction of a flat 90° bend (H)..................................................................86
Figure 105: Construction of a Tee piece (A) ......................................................................87
Figure 106: Construction of a Tee piece (2).......................................................................87
Figure 107: Construction of a Tee piece (3).......................................................................87
Figure 108: Construction of a Tee piece (4).......................................................................87
Figure 109: Construction of a 90° external bend................................................................88
Figure 110: Construction of a 90° internal bend.................................................................88
Figure 111: Construction of an offset (11) and (12) ...........................................................89
Figure 112: Construction of an offset (13) and (14) ...........................................................89
Figure 113: Earthing a cable tray.......................................................................................90
Figure 114: Cable termination............................................................................................91
Figure 115: Types of cable grips used on small household appliances. ............................92
Figure 116: Terminal connections......................................................................................92
Figure 117: Cut away the unwanted portion of the sheath.................................................93
Figure 118: Remove each layer of protection separately...................................................93
Figure 119: Typical electrician's stripping knife..................................................................94
Figure 120: Cutting the insulation with a knife ...................................................................94
Figure 121: Adjustable wire stripping pliers .......................................................................95
Figure 122: Using wire strippers ........................................................................................95
Figure 123: Set of automatic stripping (stripping and crimping) pliers ...............................96
Figure 124: Check the state of the conductors ..................................................................96
Figure 125: Preparing a stranded cable.............................................................................96
Figure 126: Pillar Terminal.................................................................................................97
Figure 127: Overtightened set screw .................................................................................98
Figure 128: Screw terminal and nut-bolt terminals............................................................98
Figure 129: Round nosed – half nosed – long and short nosed pliers ...............................98
Figure 130: Claw washer ...................................................................................................99
Figure 131: Strip connectors in moulded blocks ................................................................99
Figure 132: Connections on a strip connector ...................................................................99
Figure 133: Inserting a conductor into a terminal block .....................................................99
Figure 134: Pressure plate terminal block........................................................................100
Figure 135: Standard terminals for switchgear ................................................................100
Figure 136: Split-bolt connector .......................................................................................100
Figure 137: Types of crimped terminations (small wire sizes) .........................................101
Figure 138: Crimped connection......................................................................................101
Figure 139: Table of crimp lugs / sleeves ........................................................................102
Figure 140: Hand-operated crimping tool.........................................................................103
Figure 141: Hydraulic hand-operated crimping tool .........................................................104

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Figure 142: Hydraulically-operated crimping tool kit (hand-operated, battery, hand pump)
.................................................................................................................................104
Figure 143: Remove the insulation from the wire.............................................................104
Figure 144: Place the device on the conductor................................................................105
Figure 145: Place the connector in the crimping tool .......................................................105
Figure 146: Making a crimp connection. ..........................................................................105
Figure 147: Released Crimping Tool ...............................................................................106
Figure 148: Summary of the crimping procedure.............................................................106
Figure 149: Bottom-die crimping tool with separate hydraulic pump................................108
Figure 150: Wrong positions of wire on lugs ....................................................................108
Figure 151: Correct positions of wire on lugs...................................................................108
Figure 152: Preinsulated straight copper terminal lug......................................................109
Figure 153: Crimp in correct direction..............................................................................109
Figure 154: Crimping problems… ....................................................................................109
Figure 155: Double crimp recommendation for standard die dimensions ........................110

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Instrumentation accessories

10. TABLES
Table 1: Electrical characteristics of cable U1000 R2V ....................................................35
Table 2: Electrical characteristics of cable HO7 RN-F .......................................................37
Table 3: Construction of conductor cores .........................................................................40
Table 4: Maximum operating temperatures for the insulations ..........................................42
Table 5: Some types of instrumentation cables .................................................................45
Table 6: Temperature resistance of the insulations used on the extension or compensation
cables .........................................................................................................................47
Table 7: Cable codings ......................................................................................................48
Table 8: Compensation cable colour coding ......................................................................49
Table 9: Straight RJ45 cable..............................................................................................52
Table 10: RJ45 cable categories .......................................................................................55
Table 11: Ladder rack accessories ....................................................................................79
Table 12: Accessories for cable trays ................................................................................84
Table 13: Choice of dies for a crimping tool.....................................................................107

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