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I.L. 70C1037H02
Figure 1.4 Optional Ground Alarm/Power Supply Module
for 520M Trip Unit
1.6.2.2 Ground Fault Alarm
A ground fault alarm alerts a user to a ground fault
condition without tripping the circuit breaker. A red Alarm
Only LED on the front of the trip unit will indicate the
presence of a ground fault condition that exceeds the
programmed setting.
The ground fault alarm relay is energized when the
ground current continuously exceeds the ground fault
pickup setting for a time in excess of a 0.1 second delay.
The alarm relay will reset automatically if the ground
current is less than the ground fault pickup (see Fig-
ure 1.5, Note 4).
1.4 Wiring
The internal components of the breaker, and how they are
wired out to the breaker secondary contacts, are shown in
the breaker master connection diagram provided as
Appendix C.
1.5 Plexiglass Cover
A clear, tamper-proof, plexiglass door sits on the breaker
cover. This door allows the settings to be viewed but not
changed, except by authorized personnel. The plexiglass
cover meets applicable tamper-proof requirements. The
cover is held in place by two cover screws. Security is
insured by the insertion of a standard meter seal through
the holes in both of the cover retention screws. The
plexiglass cover has an access hole for the Step button
on the 520M and 520M
i
units.
1.6 Ground Alarm/Power Supply Module (520M Models only)
The Ground Alarm/Power Supply Module (see Figure 1.4)
is an optional accessory for the Digitrip 520M and 520M
i
models. The module can be installed beneath the metal
mounting plate of the trip unit in the Magnum Circuit
Breaker. The module covers the following input voltage
ratings: 120 VAC (7802C83G01), 230 VAC
(7802C83G02), and 24/48 VDC (7802C82G01).
1.6.1 Auxiliary Power
When the module is wired as shown in Figure 1.5, it will
provide an auxiliary power supply so that the 520M/520M
i
liquid crystal display (LCD) will be functional even when
the circuit breaker has no load. A Digitrip 520M unit
without auxiliary power will not display data until load
current reaches approximately 25% 1 phase or 10%
3 phase of the
(In) rating.
1.6.2 Ground Alarm
A second function of the module is to provide either a
ground trip or ground alarm only output contact via the
relay supplied in the module. On Digitrip 520M models
with ground fault protection, an LED on the front of the
unit also provides an indication of ground fault trip.
1.6.2.1 Ground Fault Trip
When the Ground Alarm/Power Supply module is used
with the MLSIG model, this unit will provide ground fault
trip contacts when the circuit breaker trips on a ground
fault. You must then push the Reset button on the Digitrip
in order to reset the contacts (see Figure 1.5, Note 3).
