Effective 10/2004
Page 18
I.L. 70C1036H05
Figure 2.8 Zero Sequence Sensing Scheme for Standard Circuit Breaker
Figure 2.9 Multiple Source/Multiple Ground Scheme
If the breaker is removed
from cell (B-6,B-7) jumper disconnected, Residual Ground settings will apply.
1
2
3
4
R
5
R
5
R
5
φ
φ
T
M2
M1
B5
B4
I/2
G
I/2
G
I/2
G
I/2
G
I
G
I
G
i
g
i
g
i/2
g
i/2
G
i/2
g
i/2
g
i/2
g
Neutral Sensors Wired
in a Loop Configuration
B5
B5
B4
B4
N
N
Internal
Digitrip
Sensor
Breaker M2 trips since this is the only breaker seeing the I fault via element R .
No jumper on B-6, B-7 terminals - all breakers are programmed for standard Residual Ground Fault
protection.
AUX CTs not shown. Wiring needed at system level is shown as a dotted line.
Capital letters represent primary current. Lowercase letters represent secondary current.
The three breakers (M1, M2, and T) must all have the same breaker/sensor rating.
G5
Notes:
Courtesy of NationalSwitchgear.com
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