Department of Education

10 National Capital Region

SCHOOLS DIVISION OF FICE
MARIKINA CITY

TLE - Industrial Arts

Electrical Installation and
Maintenance
First Quarter-Module 1-Part 2
Perform Roughing-in Activities for Communication and
Distribution System using Metallic Conduit

Writer: Henry T. Gallardo Jr.

Cover Illustrator: Christopher E. Mercado

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Read and analyze the statement carefully, encircle the letter of the correct answer.

1. What size of conduit can accommodate a maximum of 10 wires/conductors for

THHN #12?
a. 3/8 b. 1/2 c. 3/4 d. 1 ¼
2. What is the type of bend that makes one quarter turn?
a. offset b. elbow c. saddle d. goose neck
3. It is a type of condulets which makes conduit run turns to the right.
a. C b. LL c. LB d. LR
4. What is the tool used to thread rigid metal conduit?
a. hickey b. dies and dies stock c. reamer d. threader
5. What is the standard length of EMT?
a. 10 ft. b. 12 ft. c. 14 ft. d. 20 ft.
6. A neutral conductor shall be placed within the__________.
a. same conduit
b. the other conduit
c. separate circuit
d. anywhere
7. It is the minimum size of conduit which can be installed in industrial
occupancies
a. ½” b.3 /4” c. 1” d. 1 ½”
8. It is a type of fitting which is used to change direction.
a. connector b. coupling c. adaptor d. elbow
9. It is a short length conduit or tubing which is used to extend a conduit
system and also used between conduit and tubing such as boxes or
enclosures between two boxes.
a. connector b. coupling c. nipple d. condulets
10. It is the type of bend which is used for circuit homerun.
a. offset b. elbow c. saddle d. goose neck

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 Lesson
PEC Provisions on the Use
2 of Electrical Metallic Tubing

Electrical Metallic Tubing is a type of wiring installation which is designed to lessen

or eliminate fire hazard and electrical accident. The following the PEC Standards on
the use of electrical metallic tubing should be observed.

Technical Terms:
Circuit refers to tubing, piping or electrical wire installation, which permits flow to
and from energy source.
Circuit breaker is a safety device, which automatically open an electrical circuit if
overloaded.
Conduit is a pipe or raceway which serves as passage of electrical conductors.
EMT refers to Electrical Metallic Tubing.
Elbow is a 90 degree angle bend fitting commonly used to make quarter bend.
Galvanic reaction is a reaction between two dissimilar metals.
Hickey is a tool used to bend a conduit.
Offset is a bend used to adopt the conduit from the surface to a particular boxes or
fittings.
OHSS refers to Occupational Health and Safety Standard.
PEC refers to the Philippine Electrical code.
PPE refers to Personal Protective Equipment.
Quarter bend is a 90 degree angle bend.
Reaming refers to removal of sharp edges at the end of the pipe.
Straps are electrical wiring supports which are used to hold pipe or raceway.

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Application

Electrical metallic tubing may be used for exposed and concealed work at the same
condition with rigid metal conduit. EMT is protected with enamel should not be used
on the following conditions:

a. Subjected to mechanical during or after the construction – physical disturbance

on the raceways can cause damage on it such as minor to major cracks.
b. Cinder fill - is where the land was built up or filled using the cinders from coal
burning furnaces. When cinders get wet, an acid is formed that will destroy raceways.
c. Hazardous location – based on PEC, there are 3 classification of hazardous
location:
1. Class I – is one in which flammable gases and vapors may be present in the
air-insufficient quantities to be explosive or ignitable. E.g. petroleum refineries,
gasoline storage, dry cleaning plants, spray finishing areas.
2. Class II – is those areas made hazardous by the presence of combustible dust.
E.g. coal preparation plants, grain elevators, flour and feed mills, producers of
plastics, medicines, and fireworks.
3. Class III – are areas where easily ignitable fibers or flyings present due to the
types of materials being handled, stored, or processed. E.g. textile mills, cotton
gins, cotton seed mills and the like.
a. Exposure to corrosive fumes and – this will damage the metallic tubing once
exposed to on it.

Sizes
Electrical metallic tubing has smooth surface inside diameter. Its standard length
follows the gas pipe which is 10 ft. and a diameter from 15 mm., 20 mm up to 65
mm.

Location of some corrosive fumes and vapor

a. meat packaging plant

b. tanneries
c. salt storage plant

Under wet location

Electrical metallic tubing can be used provided the water is prevented in entering the
conduit. The support, straps and other fitting must be approved for the purpose.

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Number of conductors in tubing

The number of conductor for every single run of EMT should follow the given table.

Trade size of Size of wire No. of

conduit in mm AWG mm2 conductors
15 14 2.0 12
20 12 3.5 16
25 6 14 7
32 2 30 5

Assembly

Threadless coupling and connectors it used with tubing should be tight and should
be provided with waterproof type fitting if it will be used in wet location.

EMT fitting

Connector Coupling Adapter

Locknut Elbow Condulets

Type of EMT utility boxes and fitting

Utility Box Octagonal Box Clamps/Straps

Number of bends of EMT

The PEC states that a run of electrical conduit between outlet and outlet, between
fitting and fitting, or between outlet and fitting, will not contain more than the
equivalent of 4 quarter bends (360 degrees total) including those bends located
immediately at the outlet or fitting.

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Types of bends
The following illustrations show the different kinds of bends used in the installation
of electrical metallic tubing.

Obstacle

Elbow bend 90 Offset bend Saddle bend

Personal Protective Equipment (PPE)

Goggles Hardhat Gloves

Answer the following questions on the space provided.

(5 points each)

1. What may happen if we don’t follow the provisions under the use of EMT? Give
at least 3 examples.
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2. If you are an Electrician, what will you consider the most important among
the Provisions? Why?
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 _____________________________________________________________________
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Read and understand the direction below.

Online Learners: Using the internet, watch a video that is related to the provisions
on the use of EMT. List down the provisions you’ve watched and explain its
importance.

Offline Learners: Find an article from magazines, newspaper or other related

writings to the use of EMT and list down the provisions on it and explain its
importance.

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Write TRUE if the statement is correct and FALSE if the statement is wrong. Write
your answers on the space provided before each number.

__________1. Electrical metallic tubing is used to eliminate the fire hazards and
electrical accident.
__________2. EMT is permitted to use under the exposure of corrosive fumes and
vapors.

__________3. The standard length of EMT is 3,500 mm.

__________4. Salt storage plants is an example of location of corrosive fumes.
__________5. There are allowed 12 conductors AWG#14 for size 15 mm EMT.

__________6. Off-set bend is used on the corners or walls or floors.

__________7. The code requires a maximum of 4 quarter bends for every one run of
tubing.

__________8. Threadless couplings and connectors should be tight.

__________9. For size 25 mm EMT, there are allowed 10 conductors AGW #6.

__________10. EMT is not permitted to use on areas subjected to location with area
with easily ignitable fibers and flyings.

Draw 2 scenario that shows a place where provisions on the use of EMT. Use two
Oslo paper for this activity. You can add colors on your work.

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Book

Richter, Herbert P. and Schwan, Creighton W. Practical Electrical Wiring: 16th

Edition.

Fajardo, Max P. and Fajardo, Leo B. Electrical Layout and Estimates.

Mogado, Jomar P. Industrial Arts Specialization EIM: Trinitas Publishing, Inc.

Balana, Ulysses B. Electricity III: BEC Based

Online Source
https://filipinoengineer.com/wiki/PEC:Philippine_Electrical_Code_2009_Part_1/C
hapter_3._Wiring_Methods_and_Materials/Article_3.0_-_Wiring_Methods

http://electricaldesignii.blogspot.com/2010/02/blog-post_6694.html

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 Development Team of the Module

Writer: Henry T. Gallardo Jr. (PHS)

Editors:
Jomar P. Mogado (MNHS)
Joffre N. Albiento (MNHS)
Lauro Z. De Guzman (SH-MHS)

Internal Reviewer: Joseph T. Santos (Education Program Supervisor – EPP/TLE/TVL)

Illustrator: Christopher E. Mercado (JDPHS)
Lay-out Artist: Sheila Mae A. Malesido (SEHS)
Management Team:
Sheryll T. Gayola
Assistant Schools Division Superintendent
OIC, Office of the Schools Division Superintendent

Elisa O. Cerveza
Chief, Curriculum Implementation Division
OIC, Office of the Assistant Schools Division Superintendent

Joseph T. Santos
Education Program Supervisor – EPP/TLE/TVL

Ivy Coney A. Gamatero

EPS – Learning Resource Management and Development System

For inquiries or feedback, please write or call:

Schools Division Office – Marikina City

Email Address: sdo.marikina@deped.gov.ph
191 Shoe Ave., Sta. Elena, Marikina City, 1800, Philippines
Telefax: (02) 682-2472 / 682-3989