I have a 125hp compressor in an "EXPLOSION PROOF" building that I want to add redundant safety controls to. I have been told this is a class 1 division 1 environment. My question is can I mount conventional mechanical controls inside an enclosure while running copper tubing from there to the corresponding sensing ports. Since this is just my idea, I would like a little more info before I make a proposal to the customer. thanks in advance
Check with your insurance carrier to see if they will let you do this without a stamped (EE) print and a plan review. My guess is no.
If the enclosure is properly rated and conduit seals are in place, the code says that you CAN do this. However, just as the FAA does not really control aviation, the NEC does not control who gets to design and install.
Both instances require insurance carriers who will or will not let something "fly."
The enclosure would have to be Class 1 Div 1 and the conduit between it and the original electrical enclosure would also .
You are talking about running copper tubing from the new enclosure to the " outside " ? ( Pneumatic controls ? )
Not sure about that point ? Not sure about how to seal the exits , " legally " . Not sure about the " assembly " not being UL listed ?
Best I remember , some class 1 Div 1 are only up to 4 feet ? Maybe ? Would have to look it up ?
Is that the case with your situation ?
If so , and that is a big if , simply mount the enclosure higher than that .