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Can the ELM type ground fault modules be used on a 4 wire system?

Issue:
Can the ELM type ground fault modules be used on a 4 wire system?

Product Line:
Ground fault protection

Environment:
Electrical Distribution

Cause:
Customers need to know how to apply

Resolution:
The ELM150HD and ELM250JD Earth Leakage Module are designed for 3 wire applications only. A neutral CT is not available and they cannot be used on 4 wire applications.

The ELM can maintain accuracy for its low GF leakage sensitivity only by functioning as a zero-sequence device (one sensor for all conductors).  Adding a neutral CT would make it "modified zero-sequence" and would decrease the accuracy; in some cases this would result in nuisance tripping.  So, we don't offer a neutral CT and it can be used only on 3w systems.


CTA-ID : 2053145
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