Eaton Cutler-Hammer Digitrip 1150 - Page 17

Effective 10/2004
Page 17I.L. 70C1036H05
Figure 2.7 Source Ground Fault Sensing Scheme for Double Wide Circuit Breaker
Figure 2.6 Source Ground Fault Sensing Scheme for Standard Circuit Breaker
1150
:
1
2
3
4
1
2
3
4
Notes:
1 In this scheme, the current sensors in the circuit breaker poles are parallel-wired to achieve a 4000 Amp circuit breaker
rating. The ground fault is sensed directly via element R .
2 A on B-6, B-7 secondary contacts to program the Digitrip 1150 to use element R directly for source
ground sensing. If the circuit breaker is removed from the cell (B-6, B-7), jumper disconnected, Residual Ground setting
will apply.
3 Source ground sensor input is via B-4, B-5. Source ground current input to secondary contacts is 2A, equivalent to one
per unit ground. For example: Applying a 400:1 sensor - Use 800:2 ratio and use 800A value to calculate the ground pickup
setting.
4 The scheme is not applicable to 4-pole circuit breakers. No secondary contacts (B-4 & B-5) are available on 4-pole
circuit breakers. DO NOT jumper B-6, B-7 in 4-pole applications.
4
4
jumper is required
Courtesy of NationalSwitchgear.com