
9 – 44
Replacing Rating Plug
9.1.8
Ground-fault protection modules
WL trip units can be optionally equipped with modules that add ground fault protection. The modules provide either an alarm-only function
or alarm-and-trip functionality.
The modules can be added or removed as necessary in the field.
Settings are found on
The following combinations are possible:
The following options exist for ground-fault detection:
- Vector sum of the three phase currents plus neutral, if a neutral sensor is connected (residual sensing).
- Direct measurement of the ground-fault current using a separate 1200 A : 1 A iron-core ground fault sensor.
The direct-sense input to the trip unit has the following current-carrying capability:
- max. 1 A continuous
- max. 5 A for 0.5 sec.
NOTICE
Circuit breaker may trip.
If the trip settings are changed while the breaker is closed (and under load) the breaker may trip.
Adjust parameters only when the circuit breaker is in the open position.
Trip unit
Ground-fault protection module
ETU745
GFM A 745 (alarm only)
GFM AT 745 (alarm and trip)
ETU776
GFM A 776 (alarm only)
GFM AT 776 (alarm and trip)
Note
If the circuit breaker is applied in a 4-wire system, and residual ground
fault protection is desired, it is strongly recommended that a WL neutral
sensor (WLNCT2, WLNCT3) be used on the neutral to facilitate the
correct vector-summation of the phase currents with the neutral. Failure
to apply a neutral sensor may result in erroneous GF alarm and trips.
Note
Output of alarms and messages is possible via COM and
c
modules.
2
3
OPEN
1
Summary of Contents for UL 489
Page 36: ...5 21 Frame size II 3000 A Frame size III 1 Holes 14 mm 0720 1 0721_nu ...
Page 63: ...7 2 Horizontal connectors 0733_nu top view ...
Page 64: ...7 3 Rear vertical connectors 0734_nu top view rear view ...
Page 65: ...7 4 Front connectors 0736_nu front view top view ...
Page 66: ...7 5 Front connectors and pressure wire terminals 0737_nu top view front view ...
Page 67: ...7 6 7 2 Frame size II fixed mounted version 0494 3_nu ...
Page 68: ...7 7 Class C always 0494 5_nu top view rear view ...
Page 69: ...7 8 2500 0738_nu LH side view front view ...
Page 71: ...7 10 7 4 Frame size III fixed mounted version 0495 1_nu LH side view ...
Page 72: ...7 11 0495 2_nu top view top view ...
Page 73: ...7 12 0495 3_nu top view rear view ...
Page 75: ...7 14 7 5 Door cut outs fixed mounted circuit breaker Frame size I 0735_nu ...
Page 76: ...7 15 Frame size II III 0496_nu ...
Page 77: ...7 16 7 6 Frame size I draw out version 0745_nu ...
Page 78: ...7 17 0746_nu rear view top view ...
Page 79: ...7 18 0747_nu bottom view ...
Page 80: ...7 19 0748_nu ...
Page 81: ...7 20 0749_nu ...
Page 82: ...7 21 7 7 Frame size II draw out version 0490 1_ul ...
Page 86: ...7 25 7 8 Frame size III draw out version ...
Page 87: ...7 26 ...
Page 88: ...7 27 ...
Page 89: ...7 28 7 9 Door cut outs for draw out circuit breakers Frame size I 0750_nu ...
Page 91: ...7 30 7 11 External sensor for neutral conductor WLNCT2 ...
Page 92: ...7 31 WLNCT3 ...
Page 107: ...9 5 I tripping Ground fault tripping ...
Page 351: ......