GE Industrial Solutions ProTrip Conversion Kits LA-600, LA-800, and LA-1600 - Manual (Page 14)

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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 14.
4. On ground fault breakers serving four-wire
loads, check that the neutral sensor is properly
con nected, as indicated in Figure 14. In particu-
lar, 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
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 prob-
lem, then measure the sensor resistances. The
appro priate values are listed in Tabl e 1. Since
the phase and neutral sensors are electrically
identical, their resistances should agree closely.
Breaker CT Rating, A Resistance, ohms
LA-600
150
225
600 10.1–15.2
14.5–22
4–58
LA-800
150
400
800 10.1–15.2
27–41
51–77
LA-1600
800
1600
54–81
110–166
Table 1. CT resistance values.