Siemens MD-12HD, User Manual, Page: 40 / 74

39 Siemens Industry, Inc.
Current Transformer Basics
Ensure CTs meet the following criteria:
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600 Vac UL Rated
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UL2808 Listed
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1/3 (333 mV) output voltage
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Appropriate range for the circuit (5-120% of CT rating recommended)
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Read the label.
Ensure CT orientation and placement:
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Arrow points toward load (or as instructed by CT label).
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Arrow points away from Panel (or as instructed by CT label).
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Placed on First Conductor of voltage Reference (L1-L2) circuits are
placed on L1.
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Observe wiring color and polarity.
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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