Bul. 140U
N-Frame Circuti Breakers
Instruction Leaflet for N-Frame Circuit Breakers
WARNING
DO NOT ATTEMPT TO INSTALL OR PERFORM MAINTENANCE ON EQUIPMENT WHILE ENERGIZED.
DEATH, SEVERE PERSONAL INJURY, OR SUBSTANTIAL PROPERTY DAMAGE CAN RESULT FROM CONTACT WITH ENERGIZED EQUIPMENT. ALWAYS
VERIFY THAT NO VOLTAGE IS PRESENT BEFORE
PROCEEDING WITH THE TASK, AND ALWAYS FOLLOW GENERALLY ACCEPTED SAFETY PROCEDURES.
ALLEN-BRADLEY IS NOT LIABLE FOR THE MISAPPLICATION OR MISINSTALLATION OF ITS PRODUCTS.
The user is cautioned to observe all recommendations,
warnings, and cautions relating to the safety of personnel
and equipment as well as all general and local health and
safety laws, codes, and procedures.
The recommendations and information contained herein
are based on Allen-Bradley experience and judgement,
but should not be considered to be all-inclusive or covering every application or circumstance which may arise. If
any questions arise, contact Allen-Bradley for further
information or instruction.
1. INTRODUCTION
The N-frame circuit breaker (Fig. 1-1), is a
600 VAC maximum rated device, with an integral
trip unit and interchangeable Rating Plug. Two
continuous current ratings are available 400-800
Amp and 600-1200 Amp. Refer to table 1-1 for available
trip units and table 1-2 for available rating plugs.
40752-093(1) Effective 5/02
Fig. 1-1
N-frame Circuit Breaker
The N-Frame Trip Units are AC only devices that
employ microprocessor based technology that provides
true RMS current sensing means for proper correlation
with thermal characteristics of conductors and equipment. The primary function of the Trip Unit is circuit protection. This is achieved by analyzing the secondary
current signals received from the circuit breaker current
sensors and initiating trip signals to the circuit breaker
shunt trip when pre-set current levels and time delay settings are exceeded. Low level ground fault protection with
an adjustable time delay is supplied when appropriate trip
types are selected.
In open air at 40°C, an N-frame circuit breaker unit will
carry continuously up to 1200 amperes without
exceeding a 50°C rise at the terminals.
The calibration of the trip unit is insensitive to ambient
temperatures over a range of -20° to +55°C. However, the
trip unit contains thermal temperature protective circuitry
that initiates a trip operation for self-protection if the internal ambient temperature at the printed circuit board
(PCB) reaches approximately 90°C. For ambient conditions above 40°C, derating of the circuit breaker should
be considered to avoid exceeding a safe terminal temper-
Page 2
ature operating range. Consult Allen-Bradley for recommendations.
Molded Case Switches: The Molded Case Switch is
similar to the Circuit Breaker except that it does not have
a replaceable rating plug and has a different tripping
characteristic. There is a fixed instantaneous trip at
15,000 Ampere but there is no overload short delay or
ground fault trip. As a result sections 2.6, 2.7, 4, 5, 6.8
and 7 are not applicable. In the remaining sections the
term circuit breaker shall also include the molded case
switch.
100 Percent Rated N-Frame Circuit Breaker:
Circuit breakers are suitable for continuous
operation at 100 percent of the frame rating in an
enclosure which measures at least 42” height, 22 3/4”
width and 11 1/2” depth. The 800A version requires no
ventilation. The 1200A version requires 224 inch2 ventilation on the front face of the enclosure (72 sq. in. top, 72
sq. in. bottom, 40 sq. in. left and 40 sq. in. right). Furthermore the 1200A version has to be used with the supplied
conductor extensions and terminal barriers as shown in
Figure 2-2. Use only 90°C rated wire with ampacity
based on 75°C rated conductors. Use Copper only or
AL9CU terminals only.
Overcurrent Trip: In accordance with standards requirements, the trip unit initiates a trip of the circuit breaker
within two hours for an overcurrent of 135 percent, and a
trip in less time for higher overloads.
A “Thermal Memory” effect prevents the breaker from
being re-energized immediately after an overcurrent. A
“cooling off” period of up to 5 minutes is required, which
allows time for cabling to cool off.
Short delay/Instantaneous Trip: For short circuit conditions that exceed the short delay pick-up settings, the trip
units initiates a trip after a delay prescribed by the I2t
ramp function for trip units designated L and G. A flat
response time delay action is provided by trip units designated H unless the instantaneous (I) setting is selected.
TABLE 1-1: ELECTRONIC RMS TRIP UNIT TYPES
Trip Unit Functions
Electronic
L
Long Time
Short Time
S
●
●
●
Adjustable Ampere Setting with Fixed
Long Delay➁
●
●
●
Adjustable Short Time Pick-up with
Short Time Delay I2t Ramp
●
●
Adjustable Short Time Delay➂ with
Adjustable Short Time Pick-up, or
●
Adjustable Instantaneous Pick-up➂
●
Fixed Instantaneous (Override)➃
Ground Fault
Adjustable Ground Fault Pick-up with
Adjustable Ground Fault Time
➃
G
Fixed Ampere Rating ➀ with Fixed
Long Delay
Instantaneous
➀
➁
➂
H
●
●
●
●
Fixed rating plugs available, see table 1-2.
Optional four-setting adjustable rating plugs available, see table 1-2.
Using trip unit with adjustable delay (H), instantaneous pick-up is achieved when the lowest time delay setting (I) is selected.
Override setting fixed at frame withstand rating.
40752-093(1) Effective 5/02
Page 3
TABLE 1-2: ELECTRONIC TRIP UNIT FUNCTION AND RATING SENSING
Trip Function
Rating/Setting Description ➂
Ampere Rating
Fixed at 100%
Fixed rating plugs available
Adjustable Long
Time Pick-up
Trip Unit Ampere Rating
Fixed Rating Plugs
1200 Amp
800 Amp
600, 630➀, 700, 800, 1000, 1200, 1250➀A (In)
400, 450, 500, 550, 600, 630➀, 700, 800A (In)
Adjustable rating plugs
available
Trip Unit Ampere Rating
Adjustable Rating Plugs
1200 Amp
800 Amp
600,800,1000,1200A (In)
400,500,600,800A (In)
Short Delay Pick-up (Adjustable)
In multiples of installed rating plug amperes (In) with marks at 2-3-4-5-6-7-8x
Short Delay Time (Fixed)
I2t ramp configuration
Short Delay Time (Adjustable)
Flat response with time delay settings at 100 ms, 200 ms, and 300 ms
Instantaneous Pick-up ➁
In multiples of installed rating plug amperes (In) with marks at 2-3-4-5-6-7-8x
Ground Fault
Pick-up
(adjustable)
Trip Unit Ampere Rating
Trip Unit Setting
1200 Amp
800 Amp
200, 400, 600, 800, 1000 and 1200 Amp
200, 400, 600, 800, 1000 and 1200 Amp
Ground Fault Time Delay
Settings at instantaneous (I) 150 ms, 300 ms, and 500 ms
➀
➁
➂
Not UL listed
Occurs with short delay time adjustment set at I.
The Molded Case Switch has a fixed non-interchangeable rating plug
Ground Fault Protection: When selected, ground fault
pick-up and time delay settings shown in Table 1-2 allow
selective ground fault coordination with other circuit protection devices.
Ground Fault Alarm Unit: A ground fault alarm unit may
be used with the trip unit to provide visual indication and
a contact closure when a ground fault trip occurs. The
ground fault trip alarm unit is ordered and shipped separately if required.
Internal Accessories: Internal accessories mount on
the Digitrip trip unit. A list of internal accessories and
their instruction leaflets is provided below:
• Alarm (Signal)/Lockout (ASL) Switch
• Auxiliary Switch
• Shunt Trip
• Undervoltage Release Mechanism
(Handle Reset)
40752-094
40752-097
40752-095
40752-096
DC Application: N-Frame trip units are suitable for AC
application only.
Note: Shunt trip and undervoltage accessories, if
required, must be mounted in the left pole.
Field Testing: Test points are available for functional field
testing of the trip unit when connected to test kit.
Note: N-Frame trip unit versions with ground fault
protection are supplied with an auxiliary switch,
mounted in the right pole of the trip unit.
40752-093(1) Effective 5/02
Page 4
This instruction leaflet gives procedures for installation
and field testing of N-frame circuit breakers and
describes the different trip unit characteristics. For this
publication, the term circuit breaker shall also include the
molded case switch.
2. INSTALLATION
The installation procedure consists of inspecting the circuit breaker, installing the accessories and terminals if
required, mounting the circuit breaker, connecting the line
and load conductors and accessory wiring, adjusting the
trip settings, and installing the rating plug. Circuit breakers, accessories, terminals, and rating plugs may be supplied in separate packages. To install the circuit breaker,
perform the following steps:
2.1 Inspection
Make sure that the circuit breaker is suitable for the
intended installation by comparing nameplate data with
existing equipment ratings and system requirements.
Inspect the circuit breaker for completeness and check
for damage before mounting.
2.2 Accessory Installation
Note: If required, internal accessory installation in
any type of circuit breaker should be done before the
circuit breaker is mounted and connected. Refer to
the individual accessory instruction leaflets listed
above.
Install accessories per the accessory instruction leaflet.
CAUTION
2.4 Mounting the Circuit Breaker
WARNING
VOLTAGE IN ENERGIZED EQUIPMENT CAN CAUSE
DEATH OR SEVERE PERSONAL INJURY. BEFORE
MOUNTING THE CIRCUIT BREAKER IN AN ELECTRICAL SYSTEM MAKE SURE THERE IS NO VOLTAGE
PRESENT WHERE WORK IS PERFORMED. SPECIAL
ATTENTION SHOULD BE PAID TO REVERSE FEED
APPLICATIONS TO ENSURE NO VOLTAGE IS
PRESENT.
To mount the circuit breaker, perform the following steps:
a. For individual surface mounting, drill mounting panel
using the drilling plan shown in Fig. 2-3. For dead
front cover applications, cut out cover to correct
escutcheon dimensions, see Fig. 2-4.
b.
If circuit breaker includes factory or field installed
internal accessories, make sure the accessory wiring
can be reached when the circuit breaker is mounted.
Note: Labels with accessory connection schematic
diagrams are provided on the side of the circuit
breaker. A note should be made of the diagrams if the
labels cannot be seen when the circuit breaker is
mounted.
c.
Position circuit breaker on mounting surface.
d. Secure circuit breaker with customer supplied hardware.
2.5 Connecting Line and Load Conductors
Remove line and load end covers.
CIRCUIT BREAKER COVER CONSTRAINS MOVING
PARTS. DO NOT OPERATE THE BREAKER WITHOUT THE COVER INSTALLED.
2.3 Terminal Installation
100 Percent Rated N-Frame: Connect the supplied line
and load conductor extensions as shown in Fig. 2-2. For
a 4 pole breaker do not connect the conductor extensions
to the neutral pole.
If not already installed, mount terminals as shown in
Fig. 2-1 (100 Percent Rating Fig. 2-2). To do this, the terminal cover screws must first be loosened and the terminal covers removed.
40752-093(1) Effective 5/02
CAUTION
OVERHEATING CAN CAUSE NUISANCE TRIPPING
AND DAMAGE TO THE CIRCUIT BREAKER. WHEN
ALUMINUM CONDUCTORS ARE USED, THE APPLICATION OF A SUITABLE JOINT COMPOUND IS RECOMMENDED TO REDUCE THE POSSIBILITY OF
TERMINAL OVERHEATING.
Connect line and load conductors and accessory leads. If
the circuit breaker includes ground fault protection, connect the neutral current sensor and ground fault alarm
unit as described in section 5 and as shown in Fig 5-2.
Page 5
For bus connections use:
.500-13 bolts (English Threads)
For front mounted bus connections, socket cap screws
are recommended.
Torque Table (Domestic)
Terminal
Cat. No.
Wire Size
MCM
Cond.
Mat’l
Torq.
lb - in
1
#1 - 500 (2)
CU / AL
375
1
3/0 - 400 (3)
CU / AL
375
140U-N-TLA4 4/0 - 500 (4)
CU / AL
375
1
500 - 750 (3) CU / AL
450
1
2/0 - 500 (2)
CU ONLY
300
1
3/0 - 500 (3)
CU ONLY
300
140U-N-TLC4 3/0 - 400 (4)
CU ONLY
275
1 Contact Allen-Bradley
Fig. 2-1
Terminal Installation
Terminals are not included in the
conductor extension kit.
Terminals must be purchased
separately.
Note: Conductor extensions
increase breaker length by 3.75”
on each end.
Fig. 2-2
Conductor Extensions and Terminal Installation for 100% Rating
40752-093(1) Effective 5/02
Page 6
Fig. 2-3
Breaker Mounting Bolt Drilling Plan
Fig. 2-5
Securement of Cable (See caution note for
bracing instruction)
WARNING
HAZARDOUS VOLTAGE CONDITIONS CAN CAUSE
DEATH OR SEVERE PERSONAL INJURY. MAINTAIN
ORIGINAL ELECTRICAL CLEARANCE AND CREEPAGE SPACINGS AT TERMINATIONS.
After the circuit breaker is installed and all connections
are made, check all mounting hardware and terminal
connection hardware for torque loading. Torque values
for line/load terminal lugs are given on the circuit breaker
nameplate and table in Fig. 2-1. Torque mounting screws
to 30-35 Ib-ft. (41-47 Nm).
Re-install load end and line end covers and secure with
pan head screws provided. Torque large screws to 35-45
Ib-in. (4.0-5.0 Nm) and small screws to 24-30 Ib-in
(2.7-3.4 Nm). When prospective fault currents of cabled
installations exceed 65kA the conductors are to be
braced in accordance with Fig. 2-5.
Fig. 2-4
Circuit Breaker Escutcheon Dimension
CAUTION
UNSUPPORTED CABLES CAN CAUSE MINOR PERSONAL INJURY OR EQUIPMENT DAMAGE UNDER
SHORT CIRCUIT CONDITIONS.
40752-093(1) Effective 5/02
Page 7
Wrap conductor cables with 3/8” nylon or equivalent rope
as shown in Fig. 2-5, having a minimum tensile strength
of 2000 Ibs, at 6” from terminals and every additional 6”
with 5 wraps or every additional 1” with 1 wrap.
Note: Steps 2.6 and 2.7 are not required for the
molded case switch.
2.6 Adjusting Trip Settings
The N frame circuit breakers have the trip unit built
in as an integral part of the breaker. The trip unit is
not field replaceable. The various trip unit settings are
described in section 4. They should be adjusted as
required at this point.
2.7 Rating Plug Installation
The circuit breaker requires the installation of a rating
plug to make it operational. The installed rating plug
establishes the maximum continuous current rating (In) of
the circuit breaker. A typical rating plug is shown in
Fig. 2-6. Available rating plugs are listed in Table 1-2.
Fig. 2-7
Rating Plug Installation
e. Place a flat blade screwdriver in the slot on the
Push-to-Trip button. Press approximately 1/16 inch
and turn button 90° clockwise.
f.
If an adjustable rating plug is installed, four continuous current settings are possible. Set the switch
marked A,B,C,D to the current rating desired.
The circuit breaker is now ready for operation.
Fig. 2-6
Rating Plug
Note: The reverse procedure is used to remove the
rating plug. Turn the Push-to-Trip button to the
remove position. This action will cause the circuit
breaker to trip. Then grasp the lip of the Push-to-Trip
button and gently pull. A small screwdriver placed
under the left edge of the Push-to-Trip button will
assist in removal.
To install the rating plug perform the following steps:
Note: Before attempting to install the rating plug, the
arrow in the Push-to-Trip button portion of the plug
must be pointed toward the REMOVE position. This
can be done with a small screwdriver.
a. Position the rating plug as shown in Fig. 2-7.
b.
Make sure the arrow on the rating plug Push-to-Trip
button is pointing at REMOVE. Adjust, if necessary,
using a flat blade screwdriver.
c.
The projections on the rating plug shaft must line up
with the matching slot in the trip unit and the contact
pins must match with the sockets in the PC board.
d. Push the rating plug in as far as it will go. The electrical contact pins will enter matching holes in the trip
unit.
40752-093(1) Effective 5/02
3. OPERATION
3.1 Manual Operation
Manual operation of the circuit breaker is controlled by
the circuit breaker handle and the Push-to-Trip button.
The circuit breaker handle has three positions, two of
which are shown on the cover raised lettering to indicate
ON and OFF. On the handle, ON, OFF, and TRIP are also
shown by a color-coded strip for each circuit breaker handle position: red for ON, white for TRIP, and green for
OFF (See Fig. 3-1.). The Push-to-Trip button checks the
circuit breaker tripping function and may be used to periodically exercise the operating mechanism. The button,
located in the rating plug, is designed to be operated by
finger pressure.
Page 8
may be less than 200 Amps. If the current exceeds 200
Amps and the status light is not blinking, use the
test kit to investigate (see section 6.8).
CAUTION
LACK OF ILLUMINATION OF THE STATUS LIGHT
DOES NOT INDICATE THE TERMINALS OF THE
BREAKER ARE DEENERGIZED.
4.2 Long Time Pick Up and Delay
Fig. 3-1
Circuit Breaker Manual Controls
3.2 Circuit Breaker Reset
After an automatic or accessory initiated trip, or a manual
push-to-trip operation, the circuit breaker is reset by moving the circuit breaker handle to the extreme OFF position.
Neither the long time pick up or the long time delay are
adjustable. The long time pick up (the current at or above
which the circuit breaker will trip) occurs between 1.05
and 1.25 times In. If the status light is on steady, it indicates a trip is pending. The long delay time normally has
the characteristics t = 360 / (In)2 ±20%. For example, at In
= 6 per unit, t = 10 seconds ±20%. There is however, a
memory effect that can act to shorten the long delay. The
memory effect comes into play if a current above the long
delay pick up value exists for a time and then is cleared
by the tripping of a down stream device or the circuit
breaker itself. A subsequent overload will cause the circuit breaker to trip in shorter time than normal. The
amount of time delay reduction is inverse to the amount
of time that has elapsed since the previous overload.
Approximately five minutes is required between overloads to completely reset the memory.
4.3 Time and Pick-up Adjustments
4. N-FRAME ELECTRONIC TRIP UNIT ADJUSTMENTS
4.1 Ampere Rating
The installed rating plug establishes the maximum continuous current rating (In) of the circuit breaker. A typical rating plug is shown in Fig. 2-6. Available rating plugs are
listed in Table 1-2.
An optional adjustable rating plug provides four ampere
setting selections in a single rating plug. Fig. 4-1 shows
time/current curve details for adjustable rating plug.
Time/current curves for other adjustable rating plugs
are similar.
A green status light indicates the operational status of the
trip unit. If the load current through the circuit breaker
exceeds approximately 200 Amps the status light will
blink on and off once each second. A blinking status light
is an indication of a properly functioning trip unit. If the
status light is not blinking, the current through the breaker
40752-093(1) Effective 5/02
One to four adjustment settings are available depending
on the particular breaker purchased. An eight -position
rotary switch is provided for each. The rotary switches
are adjusted using a small flat blade screwdriver. If the
switch is turned to a setting not marked on the trip unit
nameplate, the trip unit defaults to the minimum setting.
The available settings along with the effect of changing
each setting are illustrated in Figs. 4-2 to 4-4.
4.4 Short Delay Pick-up Setting
Seven settings are available that range from 2 to 8 times
(In) as shown in Figs. 4-2 and 4-3.
4.5. Short Delay Time Setting
Four settings (I,100,200,300 milliseconds) are available
on trip units designated H (see Fig. 4-3). The I
setting gives a trip response with no intentional delay
(Instantaneous).
Page 9
4.6 Ground Fault Pick-up Setting
Six settings marked 1x through 6x IG (where IG = 200
Amps) are available (see Fig. 4-4).
Note: These ampere values are always the same no
matter what rating plug is installed in the circuit
breaker.
4.7 Ground Fault Time Settings
Four flat settings (I,150,300,500 milliseconds) are available (see Fig. 4-4). The I setting gives a trip response
with no intentional delay (instantaneous).
5. GROUND FAULT CIRCUIT BREAKERS
WARNING
BREAKER TRIP UNIT CAN BE DAMAGED BY HI-POTTING OR APPLYING EXTERNAL POWER TO ANY
COMBINATION OF THE YELLOW, GREEN, GRAY OR
WHITE LEADS. DAMAGE TO THE TRIP UNIT MAY
LEAD TO DEATH, SERIOUS PERSONAL INJURY, OR
PROPERTY DAMAGE. MAKE CONNECTIONS TO
THESE LEADS ONLY AS DIRECTED BY THIS
INSTRUCTION LEAFLET.
Ground Fault circuit breakers are supplied from the factory with one auxiliary switch with pigtail leads (red, blue
and black wires) and pigtail lead connections for a neutral
current sensor (white and grey wires) and a ground fault
alarm relay (yellow and green) wires, all installed in the
right pole of the trip unit. A neutral current sensor is provided with each trip unit. The ground fault alarm relay is
ordered and shipped separately if required.
40752-093(1) Effective 5/02
Fig. 4-1
Optional Adjustable Rating Plug
Fig. 4-2
Short Trip Current Adjustment and Curve
Details for L and G Type Trip units
Page 10
Fig. 4-3
Short Delay Trip Current and Short Delay Trip
Time Adjustment and Curve Details for H
Type Trip Unit
Fig. 5-1
Neutral Sensor Outline
40752-093(1) Effective 5/02
Fig. 4-4
Ground Fault Trip Unit Current, and Ground
Fault Trip Time Adjustment and Curve Details
Page 11
Fig. 5-2
Connection Diagrams Ground Fault Breaker - Figure indicates normal feed installation.
Neutral sensor is wired identically for reverse feed applications.
Ground fault circuit breakers detect ground fault currents
through residual sensing (they are not designed to use
source ground or zero sequence ground fault sensing
methods). If the system neutral is grounded, but no
phase to neutral loads are used, the neutral current sensor is not necessary.
If the system neutral is grounded and phase or neutral
loads are used, then the neutral current sensor (see
Fig. 5-1) must be used. It should be connected to the
breaker according to Fig. 5-2.
The neutral sensor has the same ratio as the breaker current sensors.
Note: The polarity of the sensor connections is critical. Always observe the polarity markings on the
installation drawings. To insure correct ground fault
equipment performance, conduct field test to comply
with National Electric Code requirements under article 230-95(C). See section 7 for testing instructions.
6. INSPECTION AND FIELD TESTING
The molded case circuit breakers are designed to
provide years of almost maintenance-free operation. The
40752-093(1) Effective 5/02
following procedure describes how to inspect and test a
circuit breaker in service.
Inspection
Circuit Breakers should be inspected periodically. This
inspection can be best done during normal equipment
maintenance periods when no voltage to the equipment
is available. The inspection should include the following
checks 6-1 through 6-8.
WARNING
VOLTAGES IN ENERGIZED EQUIPMENT CAN CAUSE
SEVERE PERSONAL INJURY OR DEATH. BEFORE
INSPECTING THE CIRCUIT BREAKER IN AN ELECTRICAL SYSTEM, MAKE SURE THE CIRCUIT
BREAKER IS SWITCHED TO THE OFF POSITION
AND THAT THERE IS NO VOLTAGE PRESENT
WHERE WORK IS TO BE PERFORMED. SPECIAL
ATTENTION SHOULD BE PAID TO REVERSE FEED
APPLICATIONS TO ENSURE NO VOLTAGE IS
PRESENT.
Page 12
CAUTION
7. PERFORMANCE TESTING FOR GROUND FAULT
CIRCUIT BREAKERS
7.1 Code Requirements
SOME COMMERCIAL CLEANING AGENTS WILL
DAMAGE THE NAMEPLATES OR MOLDED PARTS.
MAKE SURE THAT CLEANING AGENTS OR SOLVENTS USED TO CLEAN THE CIRCUIT BREAKER
ARE SUITABLE FOR THE JOB.
6.1 Remove dust, dirt, soil, grease, or moisture from the
surface of the circuit breaker using a lint-free dry
cloth, brush, or vacuum cleaner. Do not blow debris
into the circuit breaker. If contamination is found,
look for the source and eliminate the problem.
6.2 Switch circuit breaker to ON and OFF several times
to be sure that the mechanical linkages are free and
do not bind. If mechanical linkages are not free,
replace circuit breaker.
6.3 With the circuit breaker in the ON position, press the
PUSH-TO-TRIP button to mechanically trip the circuit breaker. Trip, reset, and switch circuit breaker
ON several times. If mechanism does not reset each
time the circuit breaker is tripped, replace the circuit
breaker.
6.4 Check base, cover, and operating handle for cracks,
chipping, and discoloration. Circuit breakers should
be replaced if cracks or severe discoloration is found.
6.5 Check terminals and connectors for looseness or
signs of overheating. Overheating will show as discoloration, melting, or blistering of conductor insulation, or as pitting or melting of conductor surface due
to arcing. If there is no evidence of overheating or
looseness, do not disturb or tighten the connections.
If there is evidence of overheating, terminations
should be cleaned or replaced. Before re-energizing
the circuit breaker, all terminations and cable should
be refurbished to the same condition as when originally installed.
6.6 Check circuit breaker mounting hardware, and
tighten if necessary.
6.7 Check area where circuit breaker is installed for any
safety hazards, including personal safety and fire
hazards. Exposure to certain types of chemicals can
cause deterioration of electrical connections.
The National Electric Code under Article 230-95-C
requires that any ground-fault protection system be performance tested when first installed. The test shall be
conducted in accordance with approved instructions provided with the equipment. A written record of this test
shall be made and shall be available to the authority having inspection jurisdiction.
7.2 Standards Requirements
As a follow-up to the basic performance requirements
stipulated by the N.E.C. as stated above in 7-1, UL Standard No. 1053 requires that certain minimum instructions
must accompany each ground fault protection system.
These following statements plus a copy of the test record
form illustrated in Fig. 7-2 are shipped with each N-frame
ground fault circuit breaker.
7.3 General Test Instructions
7.3.1 The interconnected system shall be evaluated in
accordance with the equipment assembler's detail
instruction by qualified personnel.
7.3.2 The polarity of the neutral sensor connection (if
used) must agree with equipment assembler's
detailed instructions to avoid improper operations
following apparently correct simulated test operations. Where a question exists, consult the specifying engineer and/or equipment assembler.
7.3.3 The grounding points of the system shall be verified to determine that ground paths do not exist
that would bypass the sensors. High-voltage
testers and resistance bridges may be used.
WARNING
THERE IS A HAZARD OF ELECTRICAL SHOCK OR
BURN WHENEVER WORKING IN OR AROUND ELECTRICAL EQUIPMENT. ALWAYS TURN OFF POWER
SUPPLYING BREAKER BEFORE CONDUCTING
TESTS.
Note: Since the ground fault circuit breakers derive
their operating power from the phase current, and
not from the neutral current, passing current through
the neutral sensor only will not properly test the
ground fault feature.
40752-093(1) Effective 5/02
Page 13
7.3.4 Using a low voltage (0-24V), high current, AC
source, apply a test current of 125% of the ground
fault pick-up setting through one phase of the circuit breaker, as shown in Fig. 7-1a. This should
cause the breaker to trip in less than 1 second,
and if an alarm indicator is supplied, it should
operate. Reset the breaker and the alarm indicator. Repeat the test on the other two phases.
7.3.5 If the system is a 4-wire system with a neutral current sensor, apply the same current as described
in paragraph 7.3.4 above through one phase of
the breaker, returning through the neutral sensor,
as shown in Fig. 7-1b. The breaker should not trip,
and the alarm indicator, if supplied, should not
operate. Repeat the test on the other two phases.
7.3.6 If the system is a 3-wire system with no neutral
current sensor, apply the same current as
described in paragraph 7.3.4 above through any
two phases of the breaker, with the connections
Fig. 7-1a Connections for Ground
Fault Test
40752-093(1) Effective 5/02
exactly shown in Fig. 7-1c. The breaker should not
trip, and the alarm indicator, if supplied, should not
operate.
Repeat the test using the other two combinations of
breaker phases.
CAUTION
FIELD TESTING SHOULD BE USED FOR FUNCTIONAL TESTING AND NOT FIELD CALIBRATION.
ANY TEMPORARY CONNECTION MADE FOR THE
PURPOSE OF CONDUCTING TESTS SHOULD BE
RESTORED TO PROPER OPERATING CONDITIONS
BEFORE RETURNING THE BREAKER TO SERVICE.
7.3.7 The results of the test are to be recorded on the
test form provided with the equipment.
Fig. 7-1b Connection for Ground
Fault No-Trip Test, with a
Four Wire System
Fig. 7-1c Connections for Ground
Fault No-Trip Test, with a
Three Wire System
Page 14
GROUND FAULT TEST RECORD FORM
Ground Fault Test Record should be Retained by Those in Charge of the Building’s Electrical
Installation in order to be available to the Authority having Jurisdiction.
Test Date
Fig. 7-2
Circuit
Breaker
Number
Typical Performance Test Record
40752-093(1) Effective 5/02
Results
Tested By:
Page 15
NOTES
40752-093(1) Effective 5/02
Page 16
40752-093(1) Effective 5/02
Printed in U.S.A./TQC
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