Panel board protection by NEC 1

CuriousElectron · Oct 21, 2018

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 · Oct 22, 2018

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.

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Panel board protection by NEC 1

CuriousElectron

Electrical

jraef

Electrical

Similar threads

Part and Inventory Search

Sponsor