DC High speed breaker

[pesk]

Quick question, we are installing a new hoist for a new mine. The engineers are from Canada, they have speced out a 525VDC 3000A open air high speed breaker without an enclosure. The terminations are open and the arc shute is about 24" above the ground, I do not have a NFPA book onsite but I feel this piece of equipment needs to be in a rated enclosure. The engineers claim that it meets requirements, granted its behind a fence with about 6 feet clearance. Has anyone ran into this before?

 

[petersonra]

why would it need to be in an enclosure?

in any case wouldn't this be a mine safety issue rather than a NEC issue?

 

[BPoindexter]

Is it indoor i.e a dry location or is it expsoed to the elements? MSHA is pretty strict about exposed energized parts so it may or may not be an issue with the fence around it. What type of location is it in?