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Installation
Wiring CTs
47
Building Technologies
125-202
06/06/2017
WARNING
Carefully insulate all communication lines, including shield, to prevent accidental
contact to high voltage conductors.
After wiring the communication cable, remove all scraps of wire or foil shield from
electrical utility panel.
8. Energize the MD-BMS or MD-BMED Power Meter. It is powered through the red
power connector (see wiring connections in Figure 3).
9. Verify proper power meter operation. For normal operation, the RS-485 LED blinks.
10. Close the electric equipment housing.
11. Using a voltmeter, check for high voltage. There should be no significant voltage
(no more than 5V AC or DC) from either RS-485 leg to ground. If voltage is higher
than 5V, check for incorrect wiring.
WARNING
To avoid personal injury or damage to RS-485 trunk devices, verify no significant
voltage (no more than 5V) exists on the network. The MD-BMS and MD-BMED Power
Meters are designed to be located inside high voltage switchgear. They measure
electrical use, and connect directly to the serial network.
12. Insert the CT wires into the green connector/s. See Figure 6.
NOTE:
Unused CT or Rogowski Coil inputs must be shorted with a jumper wire if all three
coils are not connected. An unconnected CT input may not show 200 current due to
stray pickup and open input.
Connecting Split-Core Millivolt CTs to a Load
NOTE:
See
Connecting a Split-Core Current Transformer to a Load Installation Instructions
(129-555), and
Connecting a Midi or Mini Hinged Split-Core Current Transformer to a
Load Installation Instructions (129-556) for detailed instructions.
1. Open the CT by holding onto the removable leg and pulling it apart.