
25 – 2
25.1
General Notes
A few facts about WL trip units and breakers will help the tester understand how best to accomplish the required testing quickly and easily.
Air Core Sensor Technology
WL Breakers are equipped with air-core current sensors (Rogowsky coils, also known as linear couplers) and, as such, the ETUs cannot be
tested by conventional secondary injection techniques.
Ground Fault Protection
WL Breaker trip units can be equipped with ground fault protection according to the table below. Ground fault protection cannot be disabled
if it has been installed at the factory. Setting the Ground Fault Mode is either done via switch (see below) or via menu
.
Figure 1
The ground fault pick-up points for the Ground Fault Alarm and Ground Fault Trip settings are independently configurable. The definitions of
the A - E dial settings are described below:
ETU Type
Available Ground Fault Modes
ETU 745
Optional: 3 or 4 wire residual, and direct sensing, are both available with additional
ground fault protection module. Mode is set by switch.
ETU 755 / 776
Optional: 3 or 4 wire residual, and direct sensing, are both available with additional
ground fault protection module. Mode is set by soft setting.
Pick-up Setting
Frame Size 1
Frame Size 2
Frame Size 3
A
100 A
100 A
400 A
B
300 A
300 A
600 A
C
600 A
600 A
800 A
D
900 A
900 A
1000 A
E
1200 A
1200 A
1200 A
Ground Fault Mode Switch
Ground Fault Trip
Pick-up Adjustment
Ground Fault Alarm
Pick-up Adjustment
Ground Fault Trip
Delay Adjustment
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: ......