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PT UNIT USER MANUAL
APRIL 2023 www.eaton.com.cn
9.3 Testing for Ground Fault Trip Units
The trip unit's display is used to observe the current being
injected and the elapsed time until trip. On the PTM software,
the test mode allows the user to enter a current to be
injected, initiate the test, observe operation, and record the
results.
This is a test to verify the trip unit's internal firmware integrity.
The test current values are simulated in the trip unit's
firmware algorithm to check its integrity.
9.3 Testing for Ground Fault Trip Units
9.3.1 Codes and Regulations
Many local or country building codes require that any ground
fault protection system be performance tested when first
installed. Conduct tests in accordance with the instructions
provided with the equipment. Make a written record of this
test and make the results available to the authority having
inspection jurisdiction.
Using PTM software, you can print out a copy of the circuit
breaker's settings to keep with the testing records.
9.3.2 Test Instructions
The wiring system must be evaluated only by qualified
personnel and in accordance with the equipment assembler's
detailed instructions.
WARNING
Electrical shock or burn injury can occur when
working on power systems. Always turn off the
main power that is supplying the circuit breaker
before conducting tests. Test out of the cell, if
possible.
To avoid improper operations following apparently correct
simulated test operations, the polarity of the neutral sensor
connections (if used) must agree with the equipment
assembler's detailed instructions. Where a question exists,
consult the specified engineer and/or equipment assembler.
Verify the grounding points of the system using high voltage
testers and resistance bridges to ensure that ground paths
do not exist that could bypass the sensors.
Use a low voltage (0 to 24 volts), high-current, AC source to
apply a test current (of 125 % of the ground pickup setting)
through one phase of the circuit breaker. This should cause
the circuit breaker to trip in less than one second and
operate the alarm indicator (if supplied). Reset the circuit
breaker and the alarm indicator. Repeat the test on the other
two phases.
Apply the same current as described above through one
phase of the circuit breaker, returning through the neutral
sensor if a neutral sensor is used. The breaker should not
trip, and the alarm indicator (if supplied) should not operate.
Repeat the test on the other two phases.
10. Maintenance of the PT Trip Unit
The trip unit itself requires no maintenance.
10.1 Replacing the Battery
The battery is provided to maintain the LED indication of
the cause of trip. A battery icon at the bottom of the display
indicates remaining battery life. The battery plays no part
in the protection function of the trip system. The battery
can be replaced at any time, even while the circuit breaker
is in-service, without affecting the operation of the circuit
breaker or its protection functions.
On the initial installation of the circuit breaker, pull out
the battery tray for removal, then remove and discard the
insulating tab, and re-insert the battery tray.
The 3 V button cell battery (CR 2032) is easily removed
and replaced; pull out remove the battery tray for removal,
remove the old battery from the holder, replace it with a
new one (observe proper polarity as marked on the tray),
and then re-insert the battery tray into the slot on the frame
module. The replacement battery should be the same type as
that already in the trip unit. Accidentally installing the battery
in the reverse direction will not harm the battery nor the trip
unit but will defeat the function of the battery.
Figure 15. Replacing the Battery
CAUTION
Exercise care when replacing the battery to ensure that
it is installed correctly. Accidentally installing the battery
in the reverse direction will not harm the trip unit nor the
battery but will defeat the function of the battery.
Trip unit’s
frame
module
Trip unit’s
control
module
