Basement/garage wiring


Old 04-07-07, 04:22 PM
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Basement/garage wiring


My question now has to do with installing receptacles and switches in a basement and garage. My garage occupies part of my basement. The walls are all 8ft concrete. I won't finish either area (i.e. I will leave the walls as-is).

So I want to install receptacles at various places around the perimeter. I also want to install light switches next to doorways leading from one section to another. Lights will just be those ceramic bases mounted onto a 3 1/2" ceiling box. Ceiling in the garage will be sheetrocked (per fire code) but the ceiling in the basement won't be.

My questions are:
1) are the receptacle and switch boxes required to be metal?

2) I'm sure I need to run conduit down the concrete wall to the box, can it be plastic conduit or must it be metal?

3) Can the conduit end at the top of the concrete wall? I assume I need to put one of those end caps on it so the wire won't be chafed by the sharp metal edge of the conduit.

4) Do I use 12/2 romex or do I use THHN.

5) If I can use romex, then in order to run a string of outlets, I'd need to run 2 cables in each conduit. Do I need to use 3/4" conduit?

6) If I use THHN, then is 1/2" conduit sufficient (assuming 6 conductors)?

7) If I use THHN, then does that mean the entire run, from breaker box to the last receptacle must be in conduit?

If you have a complete description of what is needed, I'd appreciate that very much.

Thanks for your advice now and in the past. You guys are very helpful.

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Old 04-07-07, 04:35 PM
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1) No, not in most areas.
2) Either.
3) The top end of the conduit may be open. If it's metal, you'll need a bushing to protect the cable from the rough edges. If it's PVC, just sandpaper it a bit to smooth out the edges.
4) Either, but NM-B will be easier. If you use THHN, you'll need complete conduit runs. With NM-B, you only need conduit where exposed to damage.
5) Yes, use 3/4" conduit.
6) Yes.
7) Yes.
Old 04-07-07, 06:15 PM
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John hit it all nicely.

Understand plastic(PVC) is exspensive now.
Personaly I would go with metal boxes and EMT. Use "mini" clips. This way you won't need to by a bender.These are the ones that stand the pipe off the wall (not a strap).

Use the 12/2 and 3/4" pipe. Plase a connector and plastic bushing on it to protect the wire. They also sell "change over" connectors. connector and a clamp combo.

I would go to the garage opener rec first then the light switches then the rec on the walls. The walls must be GFCI.The basement rec. aswell.

I would also recomend you run a 3 wire to the garage for a heat detector and CO detector. This will tie in with your existing hard wired smoke ckt.
You DO have them,I hope. If not, make that the first project.
Old 04-07-07, 07:27 PM
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There's a few things you said that I don't quite understand.

When you mention "mini clips" and a bender I am assuming what you're talking about is putting an "s" bend in the conduit so it lies flat against the wall and without the bends, it wouldn't be against the wall because of how it enters the box. Is this what you mean?

Actually I have a further question about this. Is it legal to do the following... Fasten a 1x6 to the concrete wall, then fasten the box and conduit to the 1x6. The reason I'd do that is because I find it much easier to ramset a piece of wood to the concrete that to fasten a metal box etc. And by doing that, I could pad out a little more behind the conduit so that plain straps could fasten it.

I didn't mention in my initial post that my basement and garage is about 2700 sqft combined. I anticipate using a fair amount of power tools in both areas. So I would run several 20 amp circuits just for receptacles.

But I didn't consider the heat and CO detectors. (This is a new house under contruction). I never wired them before. So I assume the ones in the garage are tied in with the ones in the house? Someone told me they MUST be on a lighting circuit so when the breaker pops it will be obvious. Is this true?

Old 04-07-07, 07:41 PM
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Something else that wasn't mentioned is that you need to follow your LOCAL electrical, mechanical and building codes. You will need a permit for this work and if the house is currently under construction the electrical contractor (assuming it is not you) might have a few words for you if you are doing the work at the same time as he is working on the rest of the house.

Since it seems that this is more than just adding a couple of receptacles for occasional use I think that it would be best to have the general contractor ask the electrical sub for a fixed price to include all of this into the original job. Otherwise I suggest that you wait until the house is finished and the Certificate of Occupancy is issued before you commence work.

And for what it's worth, I would use all conduit (probably PVC) and THHN/THWN wiring.
Old 04-07-07, 07:53 PM
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Mini clips leave the conduit about 1/2" the wall so you don't need to make box offsets (s bends). Use the 2x or not I would still use them.The wood would not match the knock outs in the box anyway. No code on your plan.

If you have all these tools, why not invest in a nice battery hammer drill? Install the anchors and your done.

As far as tools, do the lay out and place the rec there. dedicated ckts are always good for tools. Refer to the NEC- 210.8 for the GFCI requirements.(found on line)

As far as the smokes/heats. This depends on your area and fire dept for placment and types. The lighting ckt deal is not if the breaker pops, it is so you don't shut them off. They will all have battery back up aswell.

Don't skimp on them. Trust me when I say this.

Add: Furd is correct. Let the job finish. or get the price. any additions could affect warrenty aswell. (missed the new house)

Last edited by lectriclee; 04-07-07 at 08:06 PM.
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