Masterpact™ MP ci rcu it breaker
control units
neutral sensor
Ground fault protection may be applied on
304W or 303W circuits. On 304W an
external neutral sensor must be used.
This neutral current sensor shall have the
same ampere rating as the breaker.
location
neutral
-
main
breaker
T2
S1
ground fault
neutral CT's
ground fault protection
S1 T1
feeder
breaker
external neutral sensor
note
:
no. 18
to
14 AWG cables- max. length
60
feet
Zone Selective Interlocking
Option Z provides selectivity and reduces
the duration of fault compared to traditional
time-delayed selectivity. By interconnecting
several control units, it locates the ground
fault and allows the upstream circuit breaker
to trip at the minimum time regardless of the
time delay setting of this breaker.
ground fault
1
Circuit breaker A will clear the fault within the
minimum time delay regardless of its time
delay setting.
ground fault
2
Circuit breaker
8
will inform the upstream
circuit breaker A that it is clearing the fault
and will prevent it from tripping
instantaneously.
As a safety feature, the breaker A will trip at
the end of its time delay setting if the fault is
not cleared during this time.
note:
•
circuit breaker terminals are delivered
with "in" terminals jumpered. Remove the
jumber when interlocking with a downstream
breaker.
•
Masterpact circuit breaker with control
units ST308S- ST318S- ST408S and
ST 418S with option Z and W may be also
interlocked with Compact CK type molded
case circuit breakers with ZSI ground fault
option.
•
no. 18 to 14 AWG cables, twisted in pairs
(approx. one turn per 4").
Max. length
60
feet
Do
not ground.
MERLIN GERIN
9
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