Operating Instructions

Siemens Industry, inc. 44
Wiring the MD-xxHD Meter in a Single-Phase Application
The MD-xxHD meter is internally powered through the voltage between L1 and L2. For single-phase
installations where no L2 exists it is advised to jumper N to L2. This connection provides power to the
meter while maintaining Neutral as the metering voltage reference.
Current Transformer Basics
Ensure CTs meet the following criteria:
▪ 600 Vac UL Rated
▪ UL2808 Listed
▪ 1/3 (333 mV) output voltage
▪ Appropriate range for the circuit (5-120% of CT rating recommended)
▪ Read the label.
Ensure CT orientation and placement:
▪ Arrow points toward load (or as instructed by CT label).
▪ Arrow points away from Panel (or as instructed by CT label).
▪ Placed on First Conductor of voltage Reference (L1-L2) circuits are
placed on L1.
▪ Observe wiring color and polarity.
▪ Use the Shield wire if provided (connect to PCB terminal marked S).
Wiring Guide for CT Types
Split, Hinged, and Solid Core CTs
RōCoil CTs
White: Positive
Black: Negative
(no shield)
White: Positive
Brown: Negative
Bare Wire: Shield