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Current Transformer (CT), Potential Transformer (PT) wiring standards

Issue
What is the industry standard for current transformers (CTs) and potential transformers (PTs)? What is representation of letters H, X and S? 

Product Line
3090 SCCT, current transformers (CTs), and potential transformers (PTs)

Cause
Installation of CTs and PTs. 

Environment
Installation and wiring of CTs and PTs

*Warning: Installation and maintenance of this device should only be performed by qualified, competent personnel that have appropriate training and experience with high voltage and current devices. Failure to follow the instructions / warnings in the Meter Installation Guide can result in permanent damage to the meter, severe injury or death.  

Resolution
The industry standard for current transformers (CTs) and potential transformers (PTs) are as follows:
The Primary or Line side is designated with the letter 'H'.
The Secondary or Load side is designated with either the letter 'X' or 'S'.

X1, S1, or H1 is the positive wire.
X2, S2, or H2 is the negative wire.


Schneider Electric model SCCT current transformers identify the X1 wire as WHITE and the X2 wire as BLACK.

Note: Check with the most recent CT or PT cut sheet to verify color designation.
 

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