GE Industrial Solutions ProTrip Conversion Kits DB-75, DBL-75, DB-100, DBL-100 - Manual (Page 13)

as indicated in Figure 15. In particular, check the
following:
Breaker CT Rating, A Resistance,
ohms
DB-75
DBL-75
3000 56–68
DB-100
DBL-100
4000 72–88
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.
Table 1. CT resistance values.
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.
13