UL versus FM for explosion proof motors

[kayo]

Is there a differrence between UL and FM approval for explosion proof motors? Which is better?

 

[DRWeig]

Either is fine if you're in the US if not specified otherwise by the design engineer. It's merely a choice the motor manufacturer made when having his motor tested for an explosion-proof environment. Exception: look at the specifications for the job. They might demand FM, or they might demand UL, or they might allow either. I allow either in my specs.

Best to you,

Goober Dave

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