I'm constantly getting called out to rewire residential garages. At first, I always piped them as it seems to me that wires are very much subject to physical damage in a garage (lots of hazards in garages such as tree saws). Over time, I have realized that I'm very much in the minority, so I started using NM cable instead. Many garages have some portion sheet rocked. At the moment, I've been using RNC on those portions that are sheet rocked. However, article 334 mentions that NM cable can be run such that is "closely follows the surface". This begs the question: "Is NM secured to the surface of sheetrock compliant to the NEC"?
Hmm, interesting. It doesn't look like there is anything prohibiting you from doing it, as long as you comply with 334.15(B). I personally wouldn't do it though. You couldn't just staple directly to sheetrock, as the staples would pull out, so some type of staple/anchor would be in order. Plus, you'd have to install guard strips. It seems like a lot of time involved to just install something that looks, in my opinion, inappropriate.
I personally will stick to EMT, 4S boxes, and THHN/THWN stranded. I fasten to the drywall with Dottie nylon toggle anchors. In some limited spots, where the walls are unfinished, and I'm drilling through the top plate, I will install MC.
*edited to totally revise content. My original post seemed, in my opinion, inappropriate.
[This message has been edited by royta (edited 09-15-2004).]
Re: NM on on the surface of sheetrock Okay in a Garage?#41999 09/15/0406:52 PM09/15/0406:52 PM
334.15(B) deals with protection from physical damage & says it must be done where neccessary. That is a judgement call on the part of the AHJ.
Some AHJ's would not allow the cable to be run on the surface in a garage, others are more lenient. I've seen hundreds of exposed cable installations and I don't recall seeing much in the way of damage. Some of these installations have been around for 40 or 50 years.
My personal choice would be to use EMT or MC cable.
Few things are harder to put up with than the annoyance of a good example.
Re: NM on on the surface of sheetrock Okay in a Garage?#42000 09/16/0408:35 PM09/16/0408:35 PM
Why not fish the walls? It seems everyone wants to take the easy way out and just pipe things anymore. It looks like crap to see pipe in a home, pipe for for comm/ind not residental with the execptions of pools,hottubs things of that nature. Just my thoughts. If you are doing old work then you should be able to fish a line even, if you have to patch alittle!! if not your in the wrong business.
Re: NM on on the surface of sheetrock Okay in a Garage?#42001 09/16/0409:13 PM09/16/0409:13 PM
I'd use EMT for the whole job (I feel any exposed NM is subject to physical damage--obviously a higher standard than the NEC), but I see NM used in the county. Usually it's run on the joists similar to the way it would be run in a basement ceiling. However, when you mention surface wiring on top of sheetrock I think 334.15(B) comes into play.
Re: NM on on the surface of sheetrock Okay in a Garage?#42002 09/16/0409:28 PM09/16/0409:28 PM
I would definitely pipe it! For one thing, anywhere that I can imagine this scenario, it would likely be a service call and I would want to really "DO IT RIGHT", not just "by the book", but also "by the wallet"! Don't misunderstand me; I'm not pro-gouging or anything, but sometimes you have to make it worth your while and really do a quality installation above and beyond the NEC min. requirements. Besides, I do think that running exposed NM is a bad idea and an accident waiting to happen.
Re: NM on on the surface of sheetrock Okay in a Garage?#42003 09/17/0410:51 AM09/17/0410:51 AM
NJ Wireman, I don't disagree with you. However, when the homeowner says, "It's only a garage, I don't mind having everything on the surface", why would they want to pay more to have you fish and patch?
Re: NM on on the surface of sheetrock Okay in a Garage?#42004 09/17/0411:01 AM09/17/0411:01 AM
The question is: is running NM on the surface of GWB in a garage compliant with the NEC? The answer is, IMHO, yes, so long as it is not subject to abuse, and it is secured using the longer staples through the sheetrock and into the joists or studs. While there are many among us that think this is not the best choice, because of looks, durability and the like, it does meet the code.
Re: NM on on the surface of sheetrock Okay in a Garage?#42006 09/17/0403:34 PM09/17/0403:34 PM
In most locations that I've encountered (as a customer), 'Subject to Abuse' in places like unfinished basements results in things such as NM being run _exposed_ through (or along) the joists, but with the NM protected in pipe for the distance along walls.
It strikes me that this would be a reasonable and prudent compromise to simply having the NM running on the surface of the sheet-rock.
However if you were bidding this job you might mention that running NM exposed might raise a red flag or two, and make it harder to see the house later on...