Page 1 6
Q)
g
1
N
g
2
N
.,
c
0
I
3200 A
)
1 600 A
)
200 A
)
N
3
Main
Z 1
0.5 Sec
1 200 A
Feeder
Z2
0.3
Sec
400 A
Branch
0. 1 Sec
Z3
1 00 A
Fig. A. 1 Typical Zone Interlocking (Ground Fault Pro
tection)
M 1
0. 1
Sec
0.1 Sec
I.L. 29-8858
Notes: A1 : Wiring to be twisted pair of AWG No. 1 4
to AWG No. 20.
M2
Route Zone Interlocking wiring sepa
rate from power conductors.
DO NOT GROUND any Zone Interlock
Wiring.
A2: The maximum distance between first
and last zone is 250 feet (1 1 0 m).
A3: A Maximum of 20 breakers may be con
nected in parallel in one Zone.
Legend
= Common
( U ngrounded)
= Short Delay
Output
Signal
to Higher Level Zone
= Short Delay
I
n
p
u
t
Signal
from Lowe
r Level Zone
=
G
r
o
u
n
d
Output Signal
to Higher
Level Zone
= Ground
Input
Signal
from Lower Level Zone
�
ault
at Location
2
2
0 . 5
Sec
F21
F22
F23
0.1
Sec
0.1 Sec
0 . 1 Sec
Fig. A .2 Typical Zone Interlocking Connections with Two Main Breakers (M1, M2) and a Tie Breaker (T) (Short Delay
Protection)
Effective May 1 997
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