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Instructions for Type GFR Ground I.L. 15321-B

Fault Protection Systems File 29-700

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TABLE OF CONTENTS

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Section Page Section Page

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1.0 UL Listing . . . . . . . . . . . . . . . . . . . . 2 5.8 Connection Diagrams . . . . . . . . . . . 10
2.0 General Purpose . . . . . . . . . . . . . . . . 2 5.8.1 Relay Connections. . . . . . . . . . . 10
3. 0 Description . . . . . . . . . . . . . . . . . . . 3 5.8.2 Typical System Diagrams . . . . . . 10
4.0 Application Considerations . . . . . . . . . 4 5.8.3 Zone Differential GFR

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4.1 General . . . . . . . . . . . . . . . . . . . . 4 Operation Principles. . . . . . . . . . 10
4.2 Methods of Achieving System 6.0 Ground Fault Current Sensors . . . . . . . 10
Selectivity . . . . . . . . . . . . . . . . . . 4 6.1 General Description . . . . . . . . . . . . 10
4.2.1 Time Current Band Settings. . . . . 4 6.2 Electrical Ratings . . . . . . . . . . . . . 10
4.2.2 Zone Selective Interlocking . . . . . 4 6.2.1 Maximum System Voltage. . . . . . 10

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4.2.2.1 Zone Selective Interlock 6.2.2 Withstand . . . . . . . . . . . . . . . . 11
Wiring . . . . . . . . . . . . . . . . . 4 6.2.3 Dielectric Withstand. . . . . . . . . . 11
4.2.2.2 Zone Interlocking Operation 6.2.4 Maximum Error Signal . . . . . . . . 11
Mode . . . . . . . . . . . . . . . . . 4 7.0 Ground Fault Test Panel. . . . . . . . . . . 14
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4.3 Relay Settings. . . . . . . . . . . . . . . . 5 7.1 General Description/Purpose . . . . . . 14
4.3.1 General . . . . . . . . . . . . . . . . . . 5 7.2 Available Types. . . . . . . . . . . . . . . 15
4.3.1.1 Single Zone of Protection . . . . 5 7.3 Electrical Data . . . . . . . . . . . . . . . 15
4.3.1.2 Multiple Zones of Protection - 7.4 Operation Sequence . . . . . . . . . . . . 15
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Without Zone Interlocking . . . 5 7.4.1 Normal Operating Condition . . . . 15

4.3.1.3 Multiple Zones o f Protection - 7.4.2 If Ground Fault Occurs . . . . . . . 15
With Zone Interlocking. . . . . . 5 7.4.3 Action Required . . . . . . . . . . . . 15
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5.0 Relay Type Selection . . . . . . . . . . . . . 6 7.4.4 Test Without Service

5.1 Available Relay Types . . . . . . . . . . 6 Interruption . . . . . . . . . .. . . . . 15
5.2 Setting Adjustments. . . . . . . . . . . . 8 7.4.5 Test With Service Interruption .. . 15
5.3 Ground Fault Signal Memory. . . . . . 8 7.5 Connection Diagrams . . . . . . . . . . . 15
5.4 Time-Current Curves . . . . . . . . . . . 8 7.6 Alternate Test Diagrams . . . . . . . . . 16
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5.5 Relay Selection, General. . . . . . . . . 8 7.7 Replacement Parts . . . . . . . . . . . . . 16

5.5.1 Pick-up Range. . . . . . . . . . . . . . 8 8.0 Ground Fault Warning Indicator Relay . 18
5.5.2 Type of Selectivity . . . . . . . . . . 8 8.1 General Purpose . . . . . . . . .. . .. . . 18
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5.5.3 Type of Operation. . . . . . . . . . . 8 8.2 Available Styles. . . . . . . . . . . . . . . 18

5.6 Relay Electrical Ratings . . . . . . . . . 8 9.0 Ground Fault Indicating Ammeter . . . . 19
5.6.1 Control Power Required . . . . . . . 8 9.1 General Purpose/Description . . . . . . 19
5.6.2 Test Winding Power Required . . . 8 10.0 Performance Testing . . . . . . . . . . . . . 19
5.6.3 Output Contacts . . . . . . . . . . . . 8 10.1 Code Requirements . . . . . . . . . . . . 19
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5.6.4 Zone Interlock Contacts . . . . . . . 8 10.2 Standards Requirements . . . . . . . . . 20

5.6.5 Maximum Dielectric. . . . . . . . . . 8 10.3 General Test Instructions . . . . . . . . 22
5.7 Mounting Arrangements . . . . . . . . . 8
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Effective August, 1982 Supersedes I.L. 15321-A dated November, 1981

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......,...
..__ __ Adjusting ,_......,.._ Adjusting
Switches Switches

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Turn Screw to Turn Screw to

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lock Settings lock Settings

Ground Fault Trip

Indicator-Depress
to Reset

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Fig. lA Ground Fault Relay-Electrical Reset With Zone
Interlocking (Cat. No. GFR60El)
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Fig. lB Ground Fault Relay-Mechanical Reset With Zone
Interlocking (Cat. No. GFR60Ml)
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1.0 UL LISTED GROUND FAULT SENSING
AND RELAYING EQUIPMENT

Type GFR ground fault relays, current sensors, test panels

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and accessory devices are UL listed by Underwriters' Lab­

oratories, Inc. in accordance with their standard for
Ground Fault Sensing and Relaying Equipment, UL 1053,
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under File £48381.

2.0 GENERAL PURPOSE

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A type GFR ground fault protection system, when prop­

erly installed on a grounded electrical system, will sense
Removable Link Type
phase to ground fault currents. When the level of fault
current is in excess of the pre-selected current pick-up
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and time delay settings, the GFR relay will initiate a trip
---- Solid Core Type
action of a disconnect device, which will open the faulted
circuit and clear the fault.

The GFR devices are UL Class I devices designed to

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protect electrical equipment against extensive damage

from arcing ground faults.

CAUTION: GROUND FAULT PROTECTION SYSTEMS

DESIGNED TO PROTECT EQUIPMENT CANNOT
SIMULTANEOUSLY PROVIDE PROTECTION FOR Fig. 2 Typical Ground Fault Sensors
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PERSONNEL AGAINST ELECTRIC SHOCK HAZARDS,

SINCE THIS TYPE PROTECTION REQUIRES A SENSI­
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TIVITY IN THE LOW MILLI-AMPERE RANGE.

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3.0 DESCRIPTION

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A basic type GFR ground fault protection system consists Additional optional equipment can be added to the
of a ground fault relay (GFR) as shown in Fig. 1, a ground protection system to meet the requirements of the speci­
fault current sensor (GFS) as illustrated in Fig. 2 and a fying engineer, including:
disconnect device equipped with a shunt trip device. This

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disconnect device can be a molded case circuit breaker, 1. Ground Fault Test Panel� Fig. 4
a power circuit breaker, a bolted pressure switch or other
2. Ground Fault Warning Indicator Relay� Fig. 5
fusible disconnect device, suitable for application with

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UL Class I Ground Fault Sensing and Relaying equipment. 3. Ground Fault Indicating Ammeter (1) � Fig. 6
A typical molded case circuit breaker with a shunt trip
device installed is illustrated in Fig. 3 .

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Shunt Trip
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Fig. 3 Typical Shunt Trip Installation

Fig. 5 Ground Fault Warning Indicator Relay <D

Red Ground Fault lamps Amber Control Power lamp "ON"
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Indicates Trip Operation Only During Test Operation

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Fig. 6 Ground Fault Indicating Ammeter

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Fig. 4 Ground Fault Test Panel ©

<!l Recognized under the Component Program of Underwriters'
Laboratories, Inc.

© Changed since previous issue.

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4.0 APPLICATION CONSIDERATIONS grammed into the time-current coordination scheme

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to allow for variations in the pre-established tripping se­
4.1 General quence to allow for alternate locations of the arcing
ground fault. A zone selective interlock coordinated sys­
Type GFR ground fault protective devices are designed to tem provides for fast tripping of the nearest interrupting
be used primarily on solidly grounded electrical distribu­ device upstream of the arcing ground fault regardless of

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tion systems rated up to a maximum of 600 volts, 50/60 the pre-set time delay settings. With this type of protec­
Hz, to provide for rapid clearing of arcing ground faults. tion, the resulting systems damage level is the lowest
possible because the interrupting devices are allowed to

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When properly applied, these devices will satisfy the clear the fault as quickly as they can respond.
requirements for ground fault protection of service en­
trance equipment as outlined in Sections 2 3 0-95 and 4.2.2.I Zone Selective Interlock Wiring
517-14 of the National Electrical code. When these de­
vices are added to downstream feeder and branch circuits Zone interlock wiring is only applicable to type GFR re­

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as well as the main service disconnecting devices as sug­ lays equipped with zone selective interlocking as shown in
gested in the fine print note of 2 3 0-95 and to the down­ Table I. These relays are equipped with four additional
stream feeders as required in 517-14, additional protec­ terminals which have the following function:
tion will be provided and selective coordination of tripping
Terminal 8 - Common (Not used on 1 25V D-C GFR's)

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operations on arcing ground faults can be achieved.
9 - Output signal
10 - Input signal, time restraint
With selectively coordinated ground fault protection
11 - Input signal, no trip
equipment applied on main service disconnects and
downstream devices, a greater degree of continuity of
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To make the relays function in a zone interlocking
service is insured.
mode, all relays must be of the interlocking type and ad­
ditional wiring connections are required. Typical connec­
4.2 Methods of Achieving System Selectivity
tions for a main with multiple feeders and multiple branch
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circuits is illustrated in Fig. 7.

There are two basic methods of achieving selective coordi­
nation between different levels of ground fault protective As shown by Note I in Fig. 7, twisted pair wiring must
devices in a distribution system. be used for interlock wiring to reduce the influence of
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stray magnetic fields in switchboards with high ampacity

4.2.I TIME-CURRENT BAND SETTINGS bus systems. Interlock wiring must be routed away from
bus bars and separate from concentrated control wire
The first method employs adjustable time delay and cur­ groupings.
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rent pick-up settings to achieve selectivity between up­

stream and downstream devices. When properly coordi­ As shown by Note 3 in Fig. 7, any number - up to
nated, downstream detection devices will use a time­ 50 - type GFR relays may be wired in parallel to trans­
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current band setting that will initiate a downstream trip­ mit a single signal to upstream device. No supplementary
ping operation and clear the faulted circuit before any relaying is required for this function.
upstream interrupting device tripping action can be ini­
tiated. This type of coordination necessarily requires the 4.2.2.2 Zone Interlocking Operation Mode
longest time delay settings to be placed on the upstream
devices. This type of coordination is fine if the faults are Regardless of the time delay setting, any interlocking type
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always downstream. GFR relay will respond near instantaneously unless a re­
straint signal - which is indicative of a ground fault further
4.2.2 ZONE SELECTIVE INTERLOCKING downstream in the next protective zone - acts to change
the mode of operation to the pre-set time delay. On
In a system employing zone selective interlocking type downstream circuits, it is frequently desired that a short
devices, selective coordination is still achieved for down­ time delay be observed before a tripping action is initiated.
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stream faults by the use of time-current band settings. This can be accomplished by adding a jumper between
With appropriate settings, downstream interrupting de­ terminals 9 and 10 on the downstream relay as indicated
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vices will clear the faulted circuit before any upstream by Note 2 on Fig. 7. This jumper should not be used on
device can operate. However, with zone selective inter­ any upstream relay as it will defeat the zone interlock­
locking, additional intelligence is automatically pro- ing function.
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TypiCal Marn
Trme Delay Input
GFR

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Zone 1 TypiCal Feeder

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GFR's

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TypiCal Branch
GFR's

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Zone 3

Notes:

1. Wiring Should be Twisted Parr, Number 14 or 16 AWG With Maxrmum Distance Between Frrst and Last Zones of 250 Feet Route Separate from Power Conductors. Do Not
Ground. On 125VDC GFR's the Wire to Terminal 8 is Not Used. Only One 125VDC Source rs Allowed.
2. Jumper may be Added Between Terminals 9 and 10 on Downstream Relays to Add Trme Delay per Dial Setting. Otherwise, Relay wrll lnrtrate Tnp Wrthout Trme Delay.
3. Any Quantity-Up to 50-Relays may be Wired in Parallel to Provide a Srngle Upstream Restrarnt Srgnal.
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4. All Relays in a Zone Interlock System Must be of Interlocking Type.
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Fig. 7 Connection Diagram for Typical Zone Selective Interlocking System ©

4.3 Relay Settings be at least one step greater than the nearest downstream
device pick-up setting.
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4.3.1 GENERAL
Minimum Time Delay© - The shortest time possible
The exact individual relay time/current settings will vary should be used on the branch circuit downstream. In­
between system installations depending upon the type of crease the time delay on upstream devices in increments
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protection and level of selectivity desired. The Specifying of one step or more for molded case breakers, and two
Engineer can best make these decisions for any specific steps or more for other slower operating type devices.
installation. For general applications, settings as described
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in the following conditions may be considered. 4.3.1.3 Multiple Zones of Protection With Zone
Selective Interlocking
4.3.1.1 Single Zone Level of Protection
Establish time/current coordination as in 4. 3.1.2 for
Minimum Pick-up - 20% of disconnect rating. Increase multiple zones without zone interlocking. This is done
to maximum pick-up setting (1200 Amp) where maxi­ on the basis that most faults occur downstream and that
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mum service continuity is desired. the most downstream device should be set to clear the
fault first leaving upstream devices for back-up fault
Minimum Time Delay© - 10 cycles suggested.Any faster protection.
time will invite nuisance trips. Increase time when more
than minimum damage level can be tolerated. Add zone interlocking to provide fast tripping of up­
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stream devices regardless of pre-set time delay for faults in

4.3.1.2 Multiple Zones of Protection Without Zone
the upstream zones.
Interlocking
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Minimum Pick-Up - The pick-up setting of the down­ Where desired, nearly instantaneous operation of down­
stream device should still be no less than 20% of the stream devices can be defeated were time delayed op­
disconnect rating. Successive upstream settings should erations are adequate. See 4.2.2.2.

© Changed since previous issue.

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Table 1

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GFR Relay 120 Volt, 50/60 H z Control 120 Volt De Control
Types t!>
Style 1293C4 7 (!) Style 1293C83 <D

Cat. No. GFR ® ® Cat. No. GFR ® ®

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Pick-up In Amperes Pick-up In Amperes

1-12 5-60 100-1200 1-12 5-60 100-1200

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Electrical Reset Gil G Ol G0 3 Gil G Ol G0 3
With
Zone Interlocking 12EI 60EI 1200EI 12EID 60EID 1200EID

Electrical Reset G12 G02 G04 G12 G02 G04

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Without
Zone Interlocking 12E 60E 1200E 12ED 60ED 1200ED

Mechanical Reset G0 9 G OS G07 G0 9 G OS G07

With

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Zone Interlocking 12MI 60MI 1200MI 12MID 60MID 1200MID

Mechanical Reset Gl O G06 G08 Gl O G06 G08

Without
Zone Interlocking 12M 60M !200M 12MD 60MD 1200MD
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(l) For complete style number, add group s uffix from below, as Gll, G01, G03.
@ For complete catalog number, add s uffix from below, as 12EI, 60EI, 1200EI.
l2l All types require 120 volt, 5 0/60Hz. control for test winding.
® After March, 1983, an "A" suffix will be included after the GFR style n umber to signify that the GFR interlock is comparable
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with the SPB and Digitrip interlocks.

5.0 RELAY TYPE SELECTION (See Fig. 1) 5.2 Setting Adjustments

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5.1 Available Relay Types Each type relay is provided with two switches that are
adjustable over the range selected. The top adjusting
The GFR ground fault relays are available in two basic knob, as shown in Fig. 1, adjusts the pick-up level of the
types, ie, with and without zone selective interlocking. ground fault current. The bottom adjusting knob adjusts
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Each type relay must be reset following a trip operation. the time delay range. The calibration marks provided for
Each of the basic type relays is available with either an both adjustments are shown in Table 2.After the desired
electrically held or mechanically latched output relay. The values have been pre-set, the adjusting knobs can be
electrically held type must be electrically reset remotely - locked in position by the pointer lock screw shown in
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usually via a normally closed, momentary pushbutton in Fig. 1.

the control power circuit. In this type, a red lamp is pro­
vided for visual ground fault trip indication. The mechani­ 5.3 Ground Fault Signal Memory
cally latched type must be manually reset by depressing
the pushbutton on the face of the GFR relay.This manual Arcing ground fault currents are, by definition, erratic in
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reset bottom also serves as a mechanical pop-up trip indi­ nature being caused by the intermittent striking and re­
cator. A complete list of available styles is provided in striking of an arcing ground fault. To avoid the instanta­
Table 1. neous resetting of the solid state timing circuitry every
time the fault current drops to zero, Type GFR ground
fault relays are equipped with a memory response, which
integrates these intermittent faults with time using a seven
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second time constant.

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MINIMUM PICK· UP SETIINGS. AMPERES

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Fig. 8 GFR Relay Time-Current Curve ©

© Changed since previous issue.

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5.5.3 TYPE OF OPERATION

Table 2

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Pick-up Eledrically held relays will satisfy most applications
Amperes Dial Marking* where reliable control power is available following a fault
interruption. Where control power is derived from the
1-12 1 2 3 5 7 9 12 load side of the disconnect device and a visual trip indica­

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tion is desired, the mechanically held relay should be
5-60 5 10 15 25 35 45 60 selected. Also, in applications where the control power is
less than reliable and where an automatic reset could af­

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100-1200 100 200 300 500 700 900 1200 fect interlocking circuitry, the mechanically held relay
should be selected.
Time Delay
I© 10 15 25 35 45 60
Cycles 5.6 Relay Electrical Ratings

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*All Adjustments are in discrete steps.
5.6.1 CONTROL PO WER REQUIRED

5.4 Time/Current Curves

120 Volts, 50/60Hz., 0.125 Amps, or
The time/current performance curve of a Type GFR re­ 125 Volts de, 0.125 Amps

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lay has a flat response, ie., the operating time of any given
fault current above its pick-up setting is essentially con­ 5.6.2 TEST WINDING POWER REQUIRED©
stant. There is some small variation in the lower ranges
as indicated in Fig. 8, but very little. The pick-up and time 120 Volts, 50/60Hz., 2.5 Amps
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delay tolerances, are ± 10%.
5.6.3 OUTPUT CONTACTS

5.5 Relay Selection, General

ULHeavy Duty Pilot Rating
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The specific type and pick-up range of relay selected is

a factor of its intended application, which the specifying 240 Volts, 50/60 Hz., 3.0 Amps Continuous, 30 Amps
engineer can best determine. In general, the ratings may Inrush
be selected on the following general basis: 120 Volts, 50/60 Hz., 6.0 Amps Continuous, 60 Amps
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Inrush
5.5.1 PICK-UP RANGE 28 Volts, de, 3.0 Amps, Inductive Load
125 Volts, de, 0.5 Amps, Inductive Load
1-12 Amp - Specific circuit application where low level
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sensitivity is required. 5.6.4 ZONE INTERLOCK- CONTACTS 8-9

5-60 Amp - Individual branch and/or motor circuits Output Voltage, 6 Volts de
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where multi-level protection is provided. Rated Amps, .01 Amps, de

100-1200 Amp- General purpose and service applications. 5. 6.5 MAXIMUM DIELECTRIC

5.5.2 TYPE OF SELECTIVITY Terminals to mounting screw 3000 Volts

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Relays without zone interlocking are best suited for single 5. 7 Mounting Arrangements©
level applications where it is desired to only satisfy the
minimum requirements of the National Electrical Code. The type GFR Relay is supplied as standard in a surface
Zone selective interlocking type relays should be selected and semi-flush mounted enclosure with outline dimen­
for multi-level system applications where only the mini­ sions as illustrated in Fig. 9. For installations requiring a
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mum amount of system damage can be tolerated follow­ semi-flush cover mounting, panel cutout and mounting
ing an arcing ground fault. dimensions are illustrated in Fig. 10.
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© Changed since previous issue.

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9

m•m•" � m

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m
141 Holes
1437 _.j+-- 1437
- -r- -

Tl � -t-�
Top ,
2.719

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5.06
ct._-- I-

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Cutout
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5.750

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I Fig. 10 Semi-Flush Cover Mounting Details for Type
GFR Ground Fault Relay ©

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Fig. 9 Outline of Type GFR Ground Fault Relay ©

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Current Pick-Up
1+1
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Adjustment
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�� J
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r as -
l_L ,--__ n ln l - -- ---- -

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� z o e t er ock
� p�:re 0 11 __ ---,-,----,---' R
Zone Interlock _ _ - -
nly

� D-
1 1 1

c� �----8-�_§ j
1

-- __ ____ @] ____ � -- � ______

Trip Contacts
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(i) Omit on Mechanical Reset Relays

§

Zone Interlock Signals CD Omit on Electrical Reset Relays

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Fig. 11 Block Diagram for Typical GFR Ground Fault Relay ©

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© Changed since previous issue.

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5.8 Connection Diagrams scheme, no cross interlocking with "T" auxiliary contacts

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is required.
5. 8.1 RELAY CONNECTIONS
5.8.3.6 This scheme may be expanded to additional alter­
A simple block diagram is provided in Fig. 11 to illus­ nate sources as long as interrupting devices are available
trate the internal functional circuits of the type GFR to isolate any potential ground fault on each side of the
Relay. Complete external connections are a function of fault.

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the associated devices used with the relay along with the
complexity of the system in which the components are
6.0 GROUND FAULT CURRENT SENSORS

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applied. The terminals on the GFR relay are suitable for
(See Table 5, Page 21)
#16 through #14 AWG copper conductors. A maximum
of two per terminal are permitted.
6.1 General Description

5.8.2 TYPICAL SYSTEM DIAGRAMS

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As indicated in Table 5 (Page 21), Ground Fault Current
Basic, typical radial distribution system diagrams are pro­ Sensors (GFS) are available in a variety of physical sizes
vided in this leaflet for guidance; refer to Figs. llA, l iB, and current ratings to match the application requirements
ll C, l iD and l iE. of the distribution system. Sensors should be selected to

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match the ampere rating of the specified GFR Relay. The
Two multiple source distribution systems are illus­ physical size should be selected to properly encompass the
trated in Figs. 11F and l lH. Fig. l l F illustrates a dual required conductor configuration with space allowed for
source distribution system with center point grounding minimum clearances as shown in the applicable outline
as allowed in the National Electrical Code under Article mounting figure. Outline references are given in Table 5.
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250-23a, Exception No. 4 Fig. 11H illustrates a multiple
source, multiple ground distribution system with zone dif­ Sensors are available with solid cores having round con­
ferential ground fault sensing methods employed. ductor openings and in split core designs with various size
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rectangular openings. On the split core designs, one core

5.8.3 ZONE DIFFERENTIAL GFR OPERATION leg is removable to permit ease of installation around
.PRINCIPLES- SEE FIG. llH existing conductor assemblies.

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Ground Fault Current Sensors are special rated current
5.8.3.1 In general, will operate only for ground
transformers and must be applied only with type GFR
faults within Zone 1 and for Zone 2. This includes Relays shown in Table 1 . Sensors cannot be used with any
other equipment.
ground faults for feeders located in these respective zones.
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Sensors are insulated with cast apoxy and can be
5.8.3.2 With " M l " and "T" closed and " M2" open and
mounted directly to enclosure surfaces. Ideally, they

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with a ground fault in Zone 2, will not operate to should be installed so that all conductors passing through
R the sensor opening are physically centered in the window
trip "M 1" but, will to trip " T ".

2 opening. Minimum clearances are specified in the applica­

ble outline, but greater clearances will help reduce any

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5.8.3.3 Conversely, with "M2" and "T" closed and " M1"
possible error signals. Rectangular configurations are pro­

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open and with a ground fault in Zone 1, will not op­ vided with compensating windings to reduce potential
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error signals.
erate to trip "M2" but will to trip "T".

All sensors are provided with integral test winding for

5.8.3.4 For properly co-ordinated main, tie and feeder
use under simulated ground fault test conditions. With
interrupting devices, the feeder relays will always react
an input of 1.2 Amps into terminals 2-3, a rated output
to clear a downstream ground fault prior to operation
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of 240 M.A. should be produced in terminals 1-3 with a

of either the main or tie devices.
tolerance of ±15%. For information purposes, the turns ra­
5.8.3.5 Zone interlock wiring between upstream and tio and saturation levels of all sensors is provided in
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downstream devices can be included as shown. For this Table 5.

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6.2 Electrical Ratings

Alternate Sensor Location

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6.2.1 Maximum System Voltage

600 V.@ 50/60 Hz.

Service Source
6.2.2 WITHSTAND

Primary Amps Time Seconds

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200KA 0.05 Feeder )
50KA 0.3

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<!l 4KA Continuous

<D Except 1 KA on 12A. Solid

6.2.3 DIELECTRIC WITHSTAND

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Windings to Mounting Holes - 3 KV
Windings to Inner Core Surface - 3KV Notes:

• Zero Sequence
GFP Sensing Method
Mounting Surface to Inner Core Surface - 3KV

•MmmJUm per NEC 230-95

Type of Protection

6.2.4 MAXIMUM ERROR SIGNAL- WITH

12A Solid
60A Solid
BOLTED PHASE THROUGH FAULT

1.0 A@ 144A
5.0 A@ 720A
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•Marg1nal; Function of Feeder T1me/Current Curve AdJustabil1ty

Ground Fault Selectivity

•Not Perm1tted Downstream of ServiCe 01sconnect per NEC 250-23 (a)

*Additional Grounding

• Must Not be on Downstream S1de of Ground Fault Sensor

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1200A Solid 100 A@ 14.4KA
60/1200 A R/L 100 A@ 15 KA
Fig. liB Simple Radial System With GFR on Main
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Only-Zero Sequence Sensing

Neutral Disconnect link NEC 230· 75

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Neutral
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Feeder )
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Grounding Electrode
Conductor
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Notes:
Notes:

• Mam-Ground Return
GFP Sensing Method

•Ground Return • Feeders-Zero Sequence

GFP Sensing Method

•Mimmum per NEC 230-95 •Two level for Improved ServiCe ContmUity as Suggested by NEC 230-95(b)
Type of Protection Type of Protection

•GFP onMain Only. Ground Fau lt Sele ctivity

•Time /Current Coordmat10n BetweenMam and Downstream Feeders
• Margmal; Function of Feeder Ratmg andTime/Current Curve Ad1ustab1hty • Feeder Tnps Before Ma1n for Downstream Faults
Ground Fault Selectivity
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•Not Perm1tted Downstream of ServiCe D1sconnect per NEC 250-23(a) •Not Permitted Downstream of ServiCe D1sconnect per NEC 250-23(a)
*Additional Grounding *Additional Grounding
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Fig. llA Simple Radial System With GFR on Main Fig. IIC Simple Radial System With GFR on Main and
Only-Ground Return Sensing Feeders-Ground Return Sensing on Main
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ain on_
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�- - - z
1"' �: ���� : �_
T---'-•

�
GFS

e-1
..=,

Neutral
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"
0
Service Source N
"
Service Source

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Note: See Figure 7 lor
Interlock Wiring Details.

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Notes:

•Mam-Ground Return.
GFP Sensing Methods

• Feeders-Zero Sequence
Notes:

•Mam and Feeders-Zero Sequence

GFP Sensing Method

• Two level lor Improved Service Cont1nuity

Type of Protection

•Two level for Improved Serv1ce Continuity as Suggested byNEC 230-951b)

tM • Zone Selective Interlocking lorMinimum Arcing Fault Damage.

Type of Protection

•Time/Current Coordmat1on BetweenMam and Downstream Feeders •Time/Current Coordmation BetweenMain and Downstream Feeders.
Ground Fault Selectivity Ground Fault Selectivity

• FeederTrips BeforeMain for Downstream Faults. • FeederTnps BeforeMam lor Fault in Feeder Zone
•MamTnps Without Pre-set Time Delay lor Fault 1nMain Zone
•Not Permitted Downstream of Service Disconnect perNEC 250-23ia)
* Additional Grounding

•Must Not be on Downstream S1de of Ground Fault Sensor. •Not Permitted Downstream of Service DISconnect perNEC 250-23ia).
*Additional Grounding
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Fig. liD Simple Radial System With GFR on Main and Fig. liE Simple Radial System With GFR on Main and
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Feeders-Zero Sequence Sensing on Main Feeders With Zone Selective Interlocking

Service Source
N umber 2
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Service Source
Number 1

Note: Control Power Must be Cornman toM 1 /M2/Tte GFR Relays

,-Tnp-- -----,
Tnp
tri

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I
I
L---- M2

Neutral Disconnect
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T1e

----�.---+--� ------
'-
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Notes:
GFP Sensing Method
Return With Polar1t1es Arran:::�d to Avo1d Neutral Unbalance •T1me/Current Coardmatlon Between Mam. T1e and Feeders
Ground Fault Selectivity

Before Mam or T1e lor Downstream Faults

• Ma1n-Ground
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•T1e Tnps Before Mam to Sect1onal1ze Ma111 Bus.

• Tie-Ground Return •Feeder Tnps

Type of Pr otection
• Feeders-Zero Sequence

• An1· Additional Grounding Pomts Must be Avo1ded

*Additional Grounding

!See F1gure llG).

• Multiple level for Improved Serv1ce Cont1nu1ty
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•Zone Select1ve lnterlock1ng May be Added for MmmlUm Arcmg Fault Damage

Fig. llF Dual Source System Using Center Point Grounding (NEC 250-23a-Exception No. 4)
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GFR GFR
-
iiii1 M2

8 I 9 110 111
I I
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cp� 8 I 9 110 111
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I
�1 1
v

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GFR- n0
M2
r------<
a - Tie -,a 1-----,
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8j9 L10j11

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CDI CD:
�# Tie.� Tie__ Tie +-
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Notes:

I I (j) All Interconnections Shown

b7 -"CS
CD CD
Typical Bus 1 Feeder I Typical Bus 2 Feeder
-; Should beTwisted Pair.
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L 1-----_j
GFR GFR CD Additional Feeder GFR'sMay
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F1 Tie be Added in Parallel on Either

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Bus 1 or 2.
F2
8 I 9 110 111 �� 8 I 9llOJ11
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@ Add Cell Switch Contacts When
I II <T v
_jl Tie is Drawout Construction.
0 Steering D iodes
(Similar to 1N457)
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Fig. l lG Special Zone Interlocking Wiring that may be used with Dual Source System using Center Point Grounding
(See Figure llF)©
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Service Source Service Source
Number 1 Number 2
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;clarityMarks
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GF�
>-tft-'
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.,r-c�I� L
M1A

lGFR Tnp

I r ZSI
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l Note@ M2
ZSI I
-r---t - /M2

---zSITrip
tri

ZoneM1 _ ZoneM
Gi's�,NoteG)r-Gi's
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ZSI
L_ - - �P
*__)o,
MlB
f
____ _____ _

Phase

rr iT
M2s �:;.-
Note
-- �--�-
Neutral
-1-
T

Equipment Ground Bus

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CD - ,__, '--"--

F2 )4---i <F-Note (j)

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��!:
J
Fee r Zone
load 2 I
Notes:

•Mams/Feeders-Zero Sequence. • Zone Differential for Fault Area IsolatiOn. (j) Zone Interlock Wiring Should beTwisted
GFP Sensing Method Ground Fault Selectivity

•T1me/Cunent Coordmat1on BetweenMain and Downstream Feeders W1thm Zone. Pa1r. Refer to
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•Two level for Improved Service ContinUity • Feeder Tnps BeforeMain/Tie for Fault in Feeder Zone. CD Control Power for GFRM1, GFRM2 andT
Type of Protection 4.2.2.1.

• Zone Select1ve Interlocking forMinimum •MainTrips Without Pre-setTime Delay for Fault 1nMain Zone Should be Supplied From Common Source.
Arcing Fault Damage
• Not Permitted Downstream of Service Disconnect per NEC 250-23(a) @ Refer to 5.8.3.6
* Additional Grounding
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Fig. l lH Multiple Source, Multiple Grounded System Using Zone Differential Sensing

© Changed since previous issue.

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f---6
--- .500-------..1 Plus Panel {
t-----6.000-------.j .250 Thickness
1+-----4.688----..1

1 2 3 4 5 6 7 8 9

1.375
t2Hb0000000

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1.375

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.170 Diameter (4)
Mounting Holes

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Fig. 12 Outline of Catalog No. GFRTPD and GFRTP Ground Fault Test Panels©
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Panel Cutout

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.170 Diameter (4) � 7.0 GROUND FAULT TEST PANEL (See Fig. 4)

--t ---i- 7.1 General Description/Purpose

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The test panel is designed to test the ground fault cir­

cuitry in the type GFR Ground Fault Relay along with its
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associated disconnect with a simulated, low-level test cur­

5.000
rent from a location remote from the disconnect using a
4.63 separate power source. Provisions are available to conduct
a test in either of two operational modes: By opening the
disconnect or by not opening the disconnect.
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The test panel provides the easiest and most inexpensive

f------:��0------jf
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method to conduct ground fault tests on a repeat basis.
Tests can be conducted by qualified maintenance person­
nel during routine maintenance schedules.
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WARNING: THERE IS A HAZARD OF ELECTRICAL

Fig. 13 Panel Cutout and Drilling Plan for Catalog SHOCK OR BURN WHENEVER WORKING IN OR
No. GFRTPD and GFRTP Ground Fault AROUND ELECTRICAL EQUIPMENT. ALWAYS
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Test Panels © TURN OFF POWER SUPPLYING THIS EQUIPMENT

BEFORE WORKING INSIDE SWITCHBOARDS.

© Changed since previous issue.

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7.2 Available Types 7.4.4 TEST WITHOUT SERVICE IN TERR UPTION©

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The test panel is available only as a semi-flush, cover 1. Turn selector switch to "TEST" - Hold one second
mounted assembly under Cat. No. GFRTP or GFRTPD Red and Amber lamps turn "ON"
(for de control) as illustrated in Fig. 4. It is provided
with a selector switch for initiating the desired test 2. Turn selector switch to "RESET" - Hold six seconds

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sequence, a red lamp to signify a ground fault trip opera­ Red and Amber lamps turn "OFF"
tion, an amber lighteD to indicate the availability of test
power to the test panel, and an instruction nameplate. 3. Release selector switch - spring return to "Normal"

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Outline dimensions are shown in Fig. 12 with panel cut­
out and drilling plan details in Fig. 13. 7.4.5 TEST WITH SERVICE INTERRUPTION©

7.3 Electrical Data© 1. Depress and hold ground fault lamp

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Test Winding 2. Turn selector switch to "TEST" - Hold one second
Requires a 120 Volt, 50/60 Hz. control power source Breaker/Interrupter "OPENS"
(300 VA) for operation. Red and Amber lamps turn "ON"

Ac Control Circuit
Requires a 120 Volt, 50/60 Hz., 0.125 Amp source; use
same source as Test Winding, above. tM 3. Turn selector switch to "RESET" - Hold six seconds
Red and Amber lamps turn "OFF"

4. Release selector switch - spring return to "Normal"

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De Control Circuit
Requires a 125 Volt de, 0.125 Amp source. 5. Release ground fault lamp
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7.4 Operation Sequence 6. Reset and close breaker/interrupter

7.4.1 NORMAL OPERATING CONDITION© 7.5 Connection Diagrams

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Test Power Lamp "OFF" Fig. 14A illustrates the external connections required for
Ground Fault Lamp "OFF" a complete GFP system using 1 20 volt a-c, 50/60Hz.
Selector Switch in "NOR MAL" position control power, including: Type GFR Relay, a ground
fault sensor (GFS) and a test panel. A tabulation is also
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7.4.2 IF GRO UND FAULT OCC URS© shown to illustrate the various contact positions of the
selector switch and red lamp (switch). Fig. 14B illustrates
1. Breaker/Interrupter "OPENS" the external connections required for 1 25 volt d-e control
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2. Ground Fault lamp turns "ON" power.

7.4.3 ACTION REQUIRED Proper operation of the GFP system requires the use of
1. Locate and clear ground fault condition twisted wire connections on certain terminations. Details
2. Turn selector to "RESET" - hold six seconds are provided on the various connection diagrams including
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3. Release selector switch - spring return to "Normal" Fig. 7. Refer also to 4.2.2.1.

4. Reset and close breaker/interrupter

The terminals on the test panel are suitable for #18
through #14 AWG copper conductors. A maximum of
two per terminal of the same size and type are permitted.
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<D Note: The amber light turns "on" only during a test
sequence.
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