Enatel DC System Manual
Page 13 of 31
5.0
C
IRCUIT
B
REAKER
F
AIL
M
ONITORING
The load circuit breakers are monitored electronically through an internal general purpose input
on the monitor. The digital input will trigger an alarm when it is pulled to the system common
(+ve or –ve depending on configuration) rail. This means that to operate the load must be
connected. In this way, false alarms are avoided when no load is connected and all load circuit
breakers are in the “off” position.
Note:
This also means that a residual voltage will be measured at the load terminal even when
the circuit breaker is turned off. This is high impedance and does not present a hazard
to the user.
The battery circuit breakers however, use voltage sense to detect tripping or whether they are
turned off. This is because when a battery breaker is tripped, there may be very little voltage
difference across the breaker, making electronic fail detection problematic. Hence, if no battery
is connected, the breaker must be “on” to clear the Battery Breaker Fail alarm.
