9
Instruction Leaflet
IL29C109J
Effective November 2013
Installation Instructions for ND, HND, NDC, CND,
CHND, CNDC Circuit Breakers with Digitrip OPTIM
Trip Unit and Powernet, and/or Zone Interlock
EATON CORPORATION
www.eaton.com
NOTICE
Since the Digitrip OPTIM RMS trip units derive their
operating power from the phase currents, and not
from the neutral current, passing current through
the neutral sensor only will not properly test the
ground fault feature.
Using a low-voltage (0-24 volt), high current, ac source,
apply a test current of 125% of the Digitrip OPTIM RMS
Ground Fault Trip Unit pick-up setting through one
phase of the circuit breaker, as shown in Figure 4-2.
This should cause the breaker to trip in less than 1 sec-
ond, and if an alarm indicator is supplied, it should oper-
ate. Reset the breaker and the alarm indicator. Repeat
the test on the other
two phases.
If the system is a 4-wire system with a neutral current
sensor, apply the same current as described above
through one phase of the breaker, returning through the
neutral sensor, as shown in Figure 4-3. The breaker
should not trip, and the alarm indicator, if supplied,
should not operate. Repeat the test on the other two
phases.
Source
L
Low
Load
Current Limiting
Resistor
(if required)
Figure 4-3 Connections for Ground Fault No-Trip Test
with a Four- Wire System
If the system is a 3-wire system with no neutral current
sensor, apply the same current as described above
through any two phases of the breaker, with the con-
nections exactly as shown in Figure 4-4. The breaker
should not trip, and the alarm indicator, if supplied,
should not operate. Repeat the test using the other two
combinations of breaker phases.
CAUTION
FIELD TESTING SHOULD BE USED FOR FUNC-
TIONAL TESTING AND NOT FIELD CALIBRATION
OF THE
OPTIM RMS GROUND FAULT
TRIP UNIT.
ANY TEMPORARY CONNECTION MADE FOR THE
PURPOSE OF CONDUCTING TESTS SHOULD BE
RESTORED TO PROPER OPERATING CONDITIONS
BEFORE RETURNING THE BREAKER TO SERVICE.
The results of the test are to be recorded on the test
form provided with the equipment.
Figure 4-4 Connectionsfor Ground Fault No-Trip Test
with a Three-Wire System
L o w
V o l t a g e
S o u r c e
S o u r c e
L
C
R
C u r r e n t L i m i t i n g
R e s i s t o r
( i f r e q u i r e d )
