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SECTION 7. TESTING AND TROUBLE-
SHOOTING
WARNING: Do not change taps on the current sensors or
adjust the trip unit settings while the breaker is carrying
current. Failure to adhere to these instructions will void all
warranties.
Testing
1. Verify that the trip unit is securely installed by performing
a continuity test on the CT wiring and the trip unit.
a. Disconnect the black CT wires at each phase sensor.
b. Check for continuity with a continuity tester or VOM
from the white lead of the phase A CT to the white lead
of the phase B CT.
c. Repeat this continuity test for the white leads of the
phase A and phase C CTs.
d. Measure the resistance across each phase sensor and
compare the values measured to the values listed in
Table 1.
e. Reconnect the black CT leads to all of the phase
sensors. Ensure that this is done before continuing with
performance testing of the breaker.
Figure 21. Neutral sensor outline for 3000A through 4000A breakers
CAUTION: In addition to the continuity test described in Step
1 and before performance testing of the converted breaker,
each phase of the breaker should be primary injected with a
current level of about 10%, but no more than 20%, of the CT
rating. During the application of test current, activate the trip
unit screen by depressing the battery button on the trip unit
face and check that the test current is displayed on the screen
for each phase tested. If the trip unit fails to display the test
current, stop the test immediately and verify the installation of
the trip unit and wire harness before proceeding with any
additional testing.
WARNING: If the converted breaker is energized or tested by
primary injection with a sufficiently high test current with a
loose or open circuit between the CTs and the trip unit,
damage will occur to the trip unit, wire harness, 36-pin trip
unit connector, and CTs. Failure to adhere to these
instructions will void all warranties.
2. Check the insulation on the primary circuit with a 1,000-
volt Meggar.
3. Measure the resistance across the line and load terminals
for each phase using a micro-ohmmeter or millivolt tester.
If the resistance differs considerably from phase to phase,
13
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