GE Industrial Solutions MicroVersaTrip Plus and MicroVersaTrip PM ITE KD3000 and KE4000 - Manual (Page 3)

4. On ground fault breakers serving four-wire loads,
check that the neutral sensor is properly connected,
as indicated in Figure 21. In particular, check the
following:
a.
Verify that the neutral sensor has the same rating
and tap setting as the phase sensors.
b. Verify continuity between the neutral sensor and
its equipment-mounted secondary disconnect
block. Also check for continuity from the breaker-
mounted neutral secondary disconnect block
through to the trip unit wiring harness connector.
c. If the breaker’s lower studs connect to the power
source, then the neutral sensor must have its load
end connected to the source.
d. Verify that the neutral conductor is carrying only
the neutral current associated with the breaker’s
load current (the neutral is not shared with other
loads).
5. If the preceding steps fail to identify the problem,
then measure the sensor resistances. The appro-
priate values are listed in Table 1. Since the phase
and neutral sensors are electrically identical, their
resistances should agree closely.
Breaker CT Rating, A Resistance, Ω
LA-600
150
225
600
10.1–15.2
14.5–22
47–58
LA-1600
800
1600
54–81
110–166
Table 1. CT resistance values.
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