WL Circuit Breaker selection and application guide
54
VT / PT connections for the WL Breaker when equipped
with metering
WL power metering (“Meter Function”) can accept 3W or 4W
(LL/LN) system voltage connections.
The trip unit settings available are:
1) VT Primary Voltage (240V, 480V, 600V)
2) VT Secondary Voltage (100V, 110V, 120V)
3) VT Connection (Wye / LN, Delta / LL)
Three VTs must be used at all times.
All three VTs should be rated for the nominal system L-L voltage
(e.g. 480V) and may have either 100V, 110V or 120V secondary
voltages.
The following ratios are suggested and equivalent VTs can
be used:
240:120 = 2:1 (ITI Part # 460-240 or 468-240)
480:120 = 4:1 (ITI Part # 460-480 or 468-480)
600:120 = 5:1 (ITI Part # 460-600 or 468-600)
VT Accuracy:
Each Metering Module presents a purely resistive (unity power
factor) load to the transformer. Assuming no other devices
connected to the VT, a ITI type 486 VT can safely feed 10
metering modules and and still maintain 0.6% accuracy
assuming the wiring from the VT to the individual metering
modules is twisted pair and kept to a minimum length.
Metering VT settings:
Delta/Wye: Delta
VT Primary: 480 (for example)
VT Secondary: 120 (for example)le)
Metering VT settings:
Delta/Wye: Wye
VT Primary: 480 (for example)
VT Secondary: 120 (for example)
Low Voltage Breaker
Metering voltage details
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