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25 – 6
Also using a single source, the system can be tested to verify that the circuit breaker will not trip.
Figure 6
Circuit Breakers using Direct Sensing Ground Fault Protection via the External GF Sensor (iron core)
The WL trip units can be connected to an external 1200:1 iron core sensor to provide indication of a ground fault. This configuration
requires that the Ground Fault Mode switch be in the down (g) position. The ETU is activated by injecting 80-100A through the breaker itself
(Source A). Once the ETU is active, the test current can be injected through the external ground fault sensor to verify its connection and
polarity (Source B). The external ground fault sensor does not provide energy to the ETU to activate it.
Figure 7
The same test can be conducted using a single power source. The ETU must be activated by injecting a minimum of 100A through the
breaker itself. The external neutral sensor does not provide energy to the ETU to activate it. Multiple windings through the external sensor
can be added to simulate greater neutral currents.
Figure 8
ETU
Source
External Air-Core GF Sensor
on Neutral or Ground Bus
Secondary Terminals
X8-9 & X8-10
ETU
Source A
Source B
Secondary Terminals
X8-11 & X8-12
External Iron Core Sensor on
Neutral or Ground Bus
ETU
Source
External Iron Core GF Sensor
on Neutral or Ground Bus
Secondary Terminals
X8-11 & X8-12
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: ......