Figure 24. Example of Interlocking with Three Zones
Figure 25. ZSI Example With Mains (M1, M2) and Tie (T) Circuit Breakers
1200A
Main
800A
200A
Feeder
Branch
Zone 1
Zone 2
Zone 3
1
2
3
0.1 Sec.
100A
0.3 Sec.
400A
0.5 Sec.
1200A
Zone
1
Zone
2
Zone
3
C
ZO
ZI
C
ZO
ZI
C
ZO
ZI
See Note A4
C
= Common (Ungrounded)
–28—Contact
ZO = Zone Out Output Signal –27—Contact
ZI
= Zone In Input Signal from –29—Contact
Lower Level Zone
= Fault at location 2
Notes:
A1
: Wiring to be twisted pair of AWG #14 to #20. Route zone interlocking wiring
separate from power conductors. DO NOT GROUND any zone interlocking wiring.
A2
: The maximum distance between two farthest
breakers on different zones (from the ZO downstream
to ZI upstream terminals is 250 feet (76m).
A3
: A maximum of 20 breakers may be contained in
parallel in one zone.
A4
: Provide a self-interlocking jumper (on Zone 3) if
coordination is desired with other downstream breakers not providing the zone
interlock feature.
2
Legend
C
ZO
ZI
F11
0.1 Sec.
C
ZO
ZI
F12
0.1 Sec.
D1
1N4004
C
ZO
ZI
F21
0.1 Sec.
C
ZO
ZI
F22
0.1 Sec.
C
ZO
ZI
F23
0.1 Sec.
0.3 Sec.
C
ZO
ZI
T
C
ZO
ZI
M1
0.5 Sec.
C
ZO
ZI
M2
0.5 Sec.
C
= Common (Ungrounded)
–28—Contact
ZO = Zone Out Output Signal –27—Contact
ZI
= Zone In Input Signal from –29—Contact
Lower Level Zone
Legend
Effective September 2013
Instructional Leaflet IL01301064E
Operating Manual for Series NRX
Digitrip Trip Units 1150 / 1150i
39
EATON
www.eaton.com
