Panel board protection by NEC 1

[CuriousElectron]

Hi folks,

Is there a requirement in NEC that specifically requires a low voltage panel board to be protected by a thermal magnetic type MCCB? I have an application where I'd like to use magnetic only type breaker for a 480V panel.

Thoughts?

Thanks..

 

[jraef]

There is no approved use for a mag-only breaker in the field except as a direct one-to-one replacement for an existing one. The ONLY place they can be used is as part of a tested and listed factory built motor starter assembly where there is a separate overload relay. So the answer is not that they say you must use a thermal-mag breaker, because you could use a fuse. But you definitely CAN’T use a mag-only breaker.


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