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4.1: Wiring the Monitored Inputs and Voltages
Select a wiring diagram from Section 4.8 that best suits your application. Wire the Nexus 1250/1252
exactly as shown. For proper operation, the voltage connection must be maintained and must
correspond to the correct terminal. Program the CT and PT Ratios in the Device Profile section of
the Communicator EXT software; see the Communicator EXT User Manual for details.
The cable required to terminate the voltage sense circuit should have an insulation rating greater than
600V AC and a current rating greater than 0.1 Amp.
Use a minimum of 14 AWG wire for all phase voltage and current connections.
4.2: Fusing the Voltage Connections
For accuracy of the readings and for protection, EIG requires using 0.25-Amp rated fuses on all
voltage inputs as shown in the wiring diagrams (see section 4.8).
The Nexus Meter can handle a maximum voltage of 150V phase to neutral and 300V phase to phase.
Potential Transformers (PTs) are required for higher voltages with the standard rating. With Option -
G, the direct voltage input is extended to 300V phase to neutral and 600V phase to phase.
4.3: Wiring the Monitored Inputs - VRef
The Voltage Reference connection references the monitor to ground or neutral.
4.4: Wiring the Monitored Inputs - VAux
The Voltage Auxiliary connection is an auxiliary voltage input that can be used for any desired
purpose, such as monitoring neutral to ground voltage or monitoring two different lines on a switch.
4.5: Wiring the Monitored Inputs - Currents
Install the cables for the current at 600V AC minimum insulation. The cable connector should be
rated at 10 Amps or greater and have a cross-sectional area of 14 AWG.
Mount the current transformers (CTs) as close as possible to the meter. The following table
illustrates the maximum recommended distances for various CT sizes, assuming the connection is via
14 AWG cable.
Electro Industries/GaugeTech
Chapter 4
Electrical Installation
Doc # E107706 V1.25
4-1
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