In my 1950s-era garage, there is an ceiling outlet served by a 20A breaker that powers the garage door opener. Emerging from that surface-mounted box is a romex cable stapled to the ceiling and running down to the wall, where another surface-mounted outlet is installed with a duplex 20A outlet.
Is this to code? My wife’s grandfather, who lived here previously, was an electrical engineer, so I don’t think he’d have done anything unsafe. But code may have changed since he died in the 1970s.
The reason I ask is that I’d like to re-position the wall outlet, and simply stapling romex to the wall is something I can easily do. Installing it in conduit is probably beyond my abilities.
Is it a “finished” garage? In other words, can you see the trusses and framing, or are they covered with something (e.g. drywall, paneling)?
If it is a “finished” garage, then I don’t think exposed NM wiring is allowed. You’ll need to run the wiring behind the drywall/paneling/whatever, or run it in conduit.
I’m very much a novice about DIY electrical work, but I was able to install an outlet in my garage using EMT conduit. The hardest part is bending the conduit. You need a bender of course, and you may waste a few lengths of conduit making bad bends until you get the hang of it, but it’s not really too hard. Connecting the conduit to the junction boxes and attaching the conduit to the wall is very simple.
I have no idea if I was told correctly, but I was told that we aren’t supposed to use romex inside conduit because of heat concerns.
From what I have seen, real electricians use individual wires in conduit instead of romex.
That said, the guy who told me that we aren’t supposed to use romex in conduit is someone who I do not believe without outside supporting evidence. At the time he told me that, he was installing electrical wiring in a new commercial building using romex and none of it was in conduit.
Among other things that I saw him do is to hang the romex outside of the studs instead of through them and then the other workers nailed the rock wall sheets over it. Imagine what might happen if you were to put in a nail to hang a picture and drove it through the romex into the hot wire.
For what it’s worth, the builder for the project is now in a federal prison after being convicted of fraud involving several million dollars. That doesn’t include the people who wanted to build a new home, gave him the money in advance to secure their place in line, and ended up without the money and without the new home.
Some of the other issues with that building include:
There is a shower for workers to come in and take a shower. It was installed without a trap so the sewer gas just came up into the building. They ended up having to jackhammer the concrete floor out, install a trap, and then repour the concrete.
The builder decided to put all of the networking equipment up in the unvented attic. If you wanted to do anything, you would have to climb through the attic to the networking equipment. The company leasing the building moved the networking equipment into the bathroom. So now, you can sit on the crapper while working on the network.
The company that leased the building wanted an electrical plugin in the floor of the office. So the builder punched out a trough in the concrete, put the electrical wire in (no conduit), and refilled on top of it. The outlet plate for the electrical plugin is just a regular plastic electrical outlet plate.
Building inspections? I asked the directory of city utilities about the building inspector for the area and was told that the building inspector is headquarter in a city about 70 miles away and rarely, if ever, comes here to inspect anything. You can pretty much do whatever you want.
That almost certainly was and is a code violation. Wire “subject to physical damage” is supposed to be protected, and bare NM on a garage wall near things like moving vehicles, garden implements, people hanging things on the walls, etc. is a clear case of “subject to physical damage”. It should either be behind some kind of wallboard, in conduit, or armored cable.
If it’s just a straight run down a wall, putting it in conduit is pretty simple. You can feed the NM into a junction box with a clamp at ceiling height, transition to conduit, and then have the outlet box at the end of the conduit. You can also check out Wiremold surface-mount conduit if you don’t want to deal with EMT, although you’ll almost certainly have to switch over to individual wires (THHN/THWN) since I don’t think it comes in sizes large enough for NM cable.
There is no general rule against NM cable (popular brand “Romex”) in conduit. There are two major relevant rules:
NM is for dry locations only (it has a paper wrapper inside) and any underground conduit is by definition a “wet location” (it will eventually get wet with condensation at the very least).
The fill calculations are extremely unfavorable - it is treated as a round cable with a diameter equal to the cable width. A single 14/2 or 12/2 cable may occupy, per code, as much conduit space as a 8 or 10 or more individual conductors.
Alson, in the US, NM is rated at only 60˚C while most individual conductors are rated for at least 75˚C. Thus when derating for multiple circuits in a conduit, NM might end up requiring larger conductors.
Related to #2 above, even when complying with the NEC, physically pulling NM cable through conduit (anything other than a short, straight run) will be extremely unpleasant since it tends to twist around and kink.
For all of these reasons, it is very rare to see NM cable inside conduit.
Frankly, I’d just bite the bullet and go buy some MC cable (not AC cable) and replace the NM cable completely. The interior of the garage is a dry environment, so MC is fine when run exposed.
It’s a pain to install NM cable, especially #12, in any kind of raceway. And you don’t want to buy three separate spools of individual #12 conductors for this small job.
@ZonexandScout: thanks for the suggestion of MC cable. Although it will be a bit more expensive than I was expecting, it will probably be easier to install while definitely meeting code.
No, metal boxes are not required. You have to follow the correct grounding procedures, as well as using the proper connectors, clamps/straps, etc. But I agree that replacing the boxes with metal boxes would be a good idea.
MC cable is a bit expensive, but probably not any more expensive than trying to install some kind of raceway and pulling new conductors or cable. Probably won’t require more than a 50’ roll of #12 MC (if you can find a 50’ roll).
The task is simply to move the outlet a few feet closer to the garage door, so I can plug in our new Level 1 EVSE to charge the 2013 Nissan Leaf we just bought. Where the outlet is now, the big electronics box on the EVSE and the cable would drape inconveniently across my work table. If I move the outlet to the other side of the table I can hang the box on the wall near the outlet and the cable won’t be in the way.
I just thought of an even simpler option. Can I put a second box where I need it and run a short piece of NM along the wall to it from the existing box? Then I have two outlets instead of just one.
My bad - I thought MC couldn’t be used w/ plastic boxes.
Yea, it’s expensive. Not too bad to work with, though. To date I’ve run about 1500 feet of 12/2 MC in my barn. The sheath cutting tool makes it a lot easier.
Yesterday I bought 100 feet of 6/3 MC. Am going to install a couple 50 A outlets. $4 per foot.
Using NM cable? Surface mounting NM cable is not permitted unless you install raceway or guard strips. I’m going to stick by my “go MC cable all the way” suggestion. And it sounds like you have the opportunity to use metal boxes, so definitely do that.
I mentioned AC cable earlier. Do not use it! It looks similar to MC cable, so don’t pick up the wrong roll.
I’m pretty sure it’s okay in an unfinished garage as long as it’s being used where damage is unlikely, i.e., above vehicle height and the like. Honestly, who’s going to check on it?
Yes, if it’s run through the framing members and kept 1.25" back from the face of the framing members, it’s fine.
I doubt that the Electrical Police will come looking for violations, but it’s always a good idea to adhere to NEC, Plus, it could end up on a list of issues that need to be addressed if the house is inspected prior to sale. Not a huge issue, but it could suggest additional non-compliant work may have been done.
