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25 – 4
25.2
Primary Injection Phase Current Testing
Circuit Breakers Without Ground Fault Protection
WL Breakers equipped with trip units without ground fault protection can be easily single phase tested by injecting current into either the line
or load connection of any phase and out the opposite connection.
Figure 2
Circuit Breakers With 3- or 4-Wire Residual Ground Fault Protection
WL Breakers equipped with trip units with residual ground fault protection must be phase injected such that the ETU sees two active phases
which cancel each other out. This cancellation prevents the ground fault function from tripping. This cancellation is accomplished by inject-
ing current into the line side of one phase, out the load side, back into another load side and back out the line side.
Figure 3
If it is not possible to inject phase current into the breaker as shown in the figure above, the Ground Fault Mode switch can be used to tell the
ETU to look for a ground fault signal on a different set of terminals. As stated above, putting the Ground Fault Mode switch in the Direct
Sense position will cause the ETU to look for ground fault current on terminals X8.11 and X8.12 and not do the residual calculation. This
method can only be used if it is possible to remove the front cover of the breaker to access the switch on the side of the ETU. The switch
must be returned to its original position after testing is complete. On an ETU776, these settings are done via the LCD and keypad as there
is no physical switch.
ETU
ETU
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: ......