National Electrical Installation Standards

Standards as High as Your Own

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Friday, March 29, 2019

Question:

I have a 3 phase 480 Volt contactor. Overcurrent caused the contacts to burn a little and stick together. I pulled it apart after removing it from the circuit. My boss wants me to sand the contacts smooth and put it back in the circuit. Is that against code?

Walter Thompson

A

Answer:

There is probably not a specific NEC rule that prohibits "refinishing contacts" and there are actually contact burnishing tools available for that purpose. A lot depends on what the contacts are made of, including any plating, and the manufacturer's instructions as stated in 110.3(B). You mentioned that the contact damage was caused by overcurrent, that seems to indicate they were used above their rating, so replacing them (if the manufacturer offers replacement contacts) or replacing the controller (contactor) will probably reduce the likelihood of another problem in the future. Hopefully the cause of the overcurrent condition has also been determined and corrected.

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