Just needing some information on wiring a newly built farm building. I'm pulling 100 amps from the 400 amp service going into the house and going underground out to the building. Once in the building I have to install 4 receptacles and 4 overhead lights. Can I use MC for my wiring to the receptacles and lights or do I need to run romex or another cable through EMT to protect the wiring from phyisical damage? Does the local inspector determine what protected from phyiscal damage is? MC has permitted uses but one of it's not permitted uses is where subjected to physical damage.
FWIW, around here (Ontario Canada), NMWU (not unlike UF), is commonly used in wooden framed barns and sheds. I haven't seen conduit used, except for protection in critical places, transitioning between walls and floors, or interior "skinned" buildings (usually where a more modern farming operation is ran).
Re: Wiring a "farm building".#96690 12/20/0503:47 AM12/20/0503:47 AM
If it is in an area where animal waste can get on it... I would think it is subject to physical damage from the movement of the animals, not just thier movements... If they can crap on it, they can walk on it or kick it...
In the CITY I operate in NM, MC, UF below 8' above FF or grade, or any PVC are suject to damage any way. And all the animals are human, and tend not to crap on the wiring methods.... Maybe keep the wiring methods out of reach?
Mark Heller "Well - I oughta....." -Jackie Gleason
Re: Wiring a "farm building".#96692 12/22/0502:59 PM12/22/0502:59 PM
It's not a matter of animal waste getting on the raceways or cables, it's a matter of the vapors caused by the waste material. Those vapors can be highly corrosive. The other consideration is some of the corrosive chemicals that can be stored or used in Ag buildings.
MC cable, if used, must be of the jacketed type. The cable armor isn't sufficient in these instances. That having been said, 547.5(A) leaves quite a loophole with the phrase "...or other cables or raceways suitable for the location, with approved termination fittings..." So, a lot of this is really going to depend on what the specific use of the building will be. Best to check with the AHJ to see what he requires. Not many Ag buildings won't fall into either the Excessive Dust or Corrosive Atmosphere categories.
It's also best to give 547 a good going through. Lots of requirements there that might bite you if you're not familiar with them. And, again, a lot of it depends on what the structure will be used for.