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#96686 - 12/18/05 02:09 PM Wiring a "farm building".
kyelectric Offline

Registered: 08/30/05
Posts: 64
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.

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#96687 - 12/18/05 03:08 PM Re: Wiring a "farm building".
renosteinke Offline
Cat Servant

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
Article 547 of the NEC specifically addresses agricultural buildings.

As best I can tell, MC is allowed in farm buildings. Running romex through pipe is generally frowned upon.

Special attention should be paid to the corrosive effects of feed, fertilizer, and wash down operations. Likewise, the bonding of the frame and foundation should be done with particular care.

This is also one of those situations wher, IMO, the use of GFI breakers is justified.

#96688 - 12/19/05 05:39 AM Re: Wiring a "farm building".
JoeRossi Offline

Registered: 01/31/03
Posts: 26
Loc: Washington, NJ
Very good answer I agree.
Joe Rossi

#96689 - 12/19/05 07:52 PM Re: Wiring a "farm building".
classicsat Offline

Registered: 11/23/02
Posts: 449
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).

#96690 - 12/19/05 11:47 PM Re: Wiring a "farm building".
Tesla Offline

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
Stay away from metal....

No ordinary metal stands up to animal waste.

UF or PVC can survive.

#96691 - 12/20/05 12:37 AM Re: Wiring a "farm building".
e57 Offline

Registered: 05/27/03
Posts: 2837
Loc: S.F.,CA USA
"No ordinary metal stands up to animal waste.

UF or PVC can survive."

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

#96692 - 12/22/05 10:59 AM Re: Wiring a "farm building".
Mvannevel Offline

Registered: 03/19/03
Posts: 29
Loc: Hesperia, Michigan, USA
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.


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