Basic conduit questions

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Old 11-26-11, 03:47 PM
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Basic conduit questions

I am looking to install receptacles in my unfinished basement (poured concrete walls) and was planning to do so by running PVC conduit along the wall from box to box. So, I have a few questions:


1. What size schedule 40 would I need for either 12/2 or 14/2 wire? I plan on installing a 20amp breaker.
2. What sort of grounding wire is required? Do I need something in addition to the ground in the romex? Or is that ground sufficient?
3. Anything else I need to be aware of (other than local codes, which will be followed)? I'm just looking to get everything in order before going to code office with my final plans.
 
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Old 11-26-11, 04:10 PM
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1. What size schedule 40 would I need for either 12/2 or 14/2 wire? I plan on installing a 20amp breaker.
Your terminology implies cable not wires. Best practice is to use individual wires not cable in conduit. #14 could not be used with a 20 amp breaker.

2. What sort of grounding wire is required? Do I need something in addition to the ground in the romex? Or is that ground sufficient?
Best practice you would use three THN/THWN wires, black, white, and green or bare for ground not Romex.

3. Anything else I need to be aware of (other than local codes, which will be followed)?
The receptacles must be GFCI protected either by using a GFCI receptacle as the first one or using a GFCI breaker.

Half inch conduit should be fine for a single circuit. Use #12 on a 20 amp breaker.

Tech note: While not a code violation usually Romex is only run in conduit for short sections to protect it. In a full conduit installation individual wires are easier to use.
 
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Old 11-26-11, 04:17 PM
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Ray,
Thanks! I now see why I was confused. I'll make sure to get #12 wire (not cable ) for my install. I was planing to do a GFCI, but thanks for the reminder.

C
 
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Old 11-26-11, 04:37 PM
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Glad we could help. Post back with any other questions.
 
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Old 11-26-11, 05:29 PM
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You will only need the GFI protection in the unfinished portions of the basement. Finished basements do not require it.
 
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Old 11-26-11, 07:23 PM
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PC, thanks. The whole basement is an unfinished "finished" if that makes any sense. I'm not putting up any walls or ceilings, just painting the foundation walls, sprayed the underside of the 1st floor and will paint the floor, so I will stay on the safe side and assume it's technically unfinished.

Ray, thanks again. I'm sure when I get around to it, I'll be back!
 
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Old 11-27-11, 06:57 AM
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Originally Posted by crk530 View Post
so I will stay on the safe side and assume it's technically unfinished.
Yes that would be considered unfinished.
 
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Old 11-27-11, 07:18 AM
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While you can use PVC conduit, I'd suggest you consider EMT. I find it looks nicer since it doesn't tend to bow/droop and it provides its own grounding path. That way you just need to run a black and white 12ga wire. They have pre-bent fittings and such to make it easy to install too.

Code-wise, you're good either way.
 
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Old 11-27-11, 12:09 PM
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Boxes

What kind of boxes will you use? Metal or plastic?
 
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Old 11-28-11, 09:37 AM
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If you use metal conduit you must use metal boxes. With plastic conduit you can use plastic or metal boxes. I would use EMT metal conduit with 4x4 square boxes and raised industrial style covers. It's easy to tapcon the metal stuff to the poured wall and it's basically indestructible in a residential basement.
 
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Old 11-30-11, 12:53 PM
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I was planning on using all PVC with plastic boxes. I'm spraying the walls, so it'll all blend in to the walls, save for the receptacles themselves. I didn't really consider the EMT, but will have to take a look and consider it. I haven't submitted anything to the township as of yet.
 
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Old 11-30-11, 01:49 PM
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With both PVC and EMT you will want to come out of the box with offset nipples so the conduit lies flat against the wall. The conduit can also be bent but IMHO offset nipples are easier and look almost as good.

If you use metal boxes with PVC you will need to pigtail a ground to each box.
 

Last edited by pcboss; 11-30-11 at 03:45 PM.
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Old 11-30-11, 01:59 PM
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Ray,
Thanks. I never would've thought of that. So, ground to each recptacle and box?
 
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Old 11-30-11, 03:47 PM
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Originally Posted by crk530 View Post
Ray,
Thanks. I never would've thought of that. So, ground to each recptacle and box?
Yes if the box is metal. If the box is plastic you only need to connect to the receptacles. One wire under the screw head.
 
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