GE Industrial Solutions MicroVersaTrip Plus and MicroVersaTrip PM AK-1-15, AK-1-25 - Manual (Page 24)

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3. Verify that the wiring harness connections to the
sensors have the proper polarity (white lead to
common, black lead to tap), as shown in the
cabling diagram in Figure 46.
4. On ground fault breakers serving four-wire loads,
check that the neutral sensor is properly con-
nected, as indicated in Figure 46. In particular,
check the following:
a. Verify that the neutral sensor has the same rat-
ing and tap setting as the phase sensors.
b. Verify continuity between the neutral sensor
and its equipment-mounted secondary discon-
nect block. Also check for continuity from the
breaker-mounted neutral secondary discon-
nect block through to the trip unit wiring har-
ness 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, ohms
K-3000
K-3000S
3000 61–67
K-4000
K-4000S
4000 29–39
Table 1. CT resistance values.