Conduit required in a garage.

National Electrical Code, Article 334. NM is fine in a detached garage. When running it perpendicular to the studs, drill holes in the studs and feed the cable through the holes. When running parallel to the studs, staple it to the face of the studs (the wide side), not the edge. No need to put it in conduit.

The NEC allows NM cable to be stapled on the sides of the 2x4's and drilled through their centers. If you had drywall up and wanted to run NM on the surface, you would protect it by sleeving it in PVC or EMT, etc.

Just be sure you drill your holes and locate the romex 1 1/4" back from the front of the 2x4 so it won't get hit by a drywall screw. That pretty much means drill or staple right down the center of the 2x4. If this is closer you need metal conduit or protective metal plates.

I heard of anther electrical contractor failing inspection for this and on a recent detached garage that I did my brother (An inspector) warned me about using exposed Romex. Fortunately in my case the walls were going to be drywalled. I am in New Jersey.

Article 334.10(1) specifies it is acceptable within dwelling units. A detached garage is not a dwelling unit. Other structures must have a 15 minute thermal barrier as per 334.10(3).

I usually keep wiring, switches, and receptacles at 48" in garages as gasoline vapors sit low and I use only metal boxes so there is no question about fire rating. For exposed wiring I try to use EMT conduit (Metal) whenever possible.

Your best bet is to contact your building department to get clarification on the exposed Romex issue.

Take a look at . I agree with those who say that since a detached garage is not a dwelling unit, the use of NM cable is subject to the requirements of NEC 334.10(3). That means NM can only be used if covered by a 15 minute fire-rated finish, i.e. drywall. You could use MC instead.

Cheers, Wayne

Wayne, Others, Thanks for the help. It looks as if all types of NM cable (NM, NMC, NMS) are out as per the "dwelling" issue of a detached garage as per 334.10 . Then conduit or metallic cable it is!

Ed

Wayne Whitney wrote:

Interesting what one learns on newsgroups.

You could also ask the inspector if they allow NM.

Depending on how much wiring you need to do, you mind find it easier to cover the NM with drywall--I don't think you'd need to drywall the whole garage. On the other hand, I believe MC cable is easy to use, but haven't tried it myself.

Cheers, Wayne

Also in some cities ( Like Chicago and burbs ) most all wiring must be in metal pipe and boxes inside of buildings.

That is the right answer. "subject to physical damage" is always a judgement call and different AHJs see it differently. Some are happy with Romex on running boards and others want greater degrees of protection. The question of whether you can use exposed Romex in a residential garage is also a local call.