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-   -   Bending EMT conduit around 90 degree corner (http://www.diychatroom.com/f18/bending-emt-conduit-around-90-degree-corner-16913/)

alvanos 02-11-2008 07:45 AM

Bending EMT conduit around 90 degree corner
 
Hi all, first time posting here. I'm going to do my best to explain my situation, without having a piece of paper to draw my picture on :)

I just finished framing out my basement, and I'm on to the electrical. I live in Chicago-land, a part of the country where thinwall/EMT conduit is required by code. So I bent a 90 degree turn to take it around an inside corner. I notched out the studs to lay the conduit across, but when I went to put it back into the notches, well the 90 degree curve that the conduit bender makes is so gradual, that the EMT doesn't fit into the notch without sticking out to where the drywall would be (on the turn that is). If I notch any further, I'll be cutting the studs clear though. I hope this description of my problem is adequate, and that somebody can help me out. Thanks!!
Adam

moneymgmt 02-11-2008 07:58 AM

I've been wrong before, but you can't put a perfect 90 degree corner in tubing... it will collapse and crease. Don't they have elbows joints for what you need?

jbfan 02-11-2008 08:33 AM

There are some electricians from Chicagoland that might help you. I have never had tp put conduit inside a wall like you are doing.

alvanos 02-11-2008 08:41 AM

Quote:

Originally Posted by moneymgmt (Post 96821)
I've been wrong before, but you can't put a perfect 90 degree corner in tubing... it will collapse and crease. Don't they have elbows joints for what you need?

Yes, I'm sure that I can get a 90 degree coupling, but my understanding is that one should avoid sharp 90's since it makes pulling wire harder. But you might be right, that this is the only way. Let's see if anybody else can chime in.

AllanJ 02-11-2008 09:18 AM

I would not cut studs away considerably.

Would this work: Use a 90 degree conduit elbow or coupling which has a flap on one side and you pull the wires as far as and out of the elbow and then do another pull to continue the wires (no splices) down the conduit.

J. V. 02-11-2008 09:27 AM

Put a box near the corner. Not in the corner. Then go up over and down to the next box. I understand your question as I run into this exact situation many times before. I never run conduit horizontally through studs. I always mount all the boxes, stub the conduit up above the ceiling, then use a connector (1). You will use more pipe and wire, but it is much easier. Contractors do this to save time. Don't use any conduit bodies behind the wall. You will fail the inspection.

alvanos 02-11-2008 01:08 PM

Quote:

Originally Posted by AllanJ (Post 96853)
I would not cut studs away considerably.

Would this work: Use a 90 degree conduit elbow or coupling which has a flap on one side and you pull the wires as far as and out of the elbow and then do another pull to continue the wires (no splices) down the conduit.

This I could do, and I'm thinking about it ... the only problem being once the drywall is up, I loose the ability to pull new wire. But the more I ponder this, it may be my only option.

alvanos 02-11-2008 01:11 PM

Quote:

Originally Posted by J. V. (Post 96856)
Put a box near the corner. Not in the corner. Then go up over and down to the next box. I understand your question as I run into this exact situation many times before. I never run conduit horizontally through studs. I always mount all the boxes, stub the conduit up above the ceiling, then use a connector (1). You will use more pipe and wire, but it is much easier. Contractors do this to save time. Don't use any conduit bodies behind the wall. You will fail the inspection.

Hi J.V., I would do this, except the wall in question is a half-wall in a basement, hence no real way to come from the ceiling. This job is a gut-and-redo, and there was no receptacle on this wall before; I'm guessing they didn't want to deal with what I'm dealing with now; instead there were just two receptacles, one on each partition wall. I could leave out the receptacle, but that would technically be a code violation. What are your thoughts on the EMT Inside Corner Elbows that some have mentioned (such as this one: (http://www.lowes.com/lowes/lkn?actio...9-15527-49591).

Thanks,
Adam

joed 02-11-2008 03:19 PM

Quote:

Originally Posted by AllanJ (Post 96853)
I would not cut studs away considerably.

Would this work: Use a 90 degree conduit elbow or coupling which has a flap on one side and you pull the wires as far as and out of the elbow and then do another pull to continue the wires (no splices) down the conduit.

Can't put that coupler inside a wall. The removable flap needs to remain accessible.

Stubbie 02-11-2008 03:32 PM

1 Attachment(s)
Use a pull elbow these will allow pulling in new wires even if unaccessible. But I would suggest pulling in an extra branch circuit to begin with rather than later because you generally have to sacrifice an existing wire to pull in new ones if you don't install a pull string to begin with. Or a piece of FMC will always work in the corner if it is 1/2" size between boxes. Don't know if Chicago allows flexible metal conduit or not. Also an LL or LR (LL shown in image) emt body will work but may be hard to pull thru if wire is pulled at a later date for new circuits and you don't have access to the cover. Use nail plate covers over your notches (first image).

http://secure2.data-comm.com/stores/...alog/61352.jpg

http://www.bptfittings.com/images/products/61dc.gif

http://www.bptfittings.com/images/products/ll-31.gif

chris75 02-11-2008 04:05 PM

Can you go up then back down instead of trying to go around the corner?

Stubbie 02-11-2008 04:19 PM

Joe

It is there only for ease of pulling and you can pull through these even if not accessible. But you cannot fish through them so you need a pull string or installed wire to begin with to use at a later date. The cover only needs to be accessible after finish if you make a splice which you would never do in a pull elbow.

chris75 02-11-2008 04:31 PM

Quote:

Originally Posted by Stubbie (Post 96986)
Joe

It is there only for ease of pulling and you can pull through these even if not accessible. But you cannot fish through them so you need a pull string or installed wire to begin with to use at a later date. The cover only needs to be accessible after finish if you make a splice which you would never do in a pull elbow.

You cannot bury that fitting... with or without a splice

Stubbie 02-11-2008 06:05 PM

Chris

Very good catch, I was thinking there was an exception for listed pulling elbows and condelet bodies, however after checking NEC 314.29 it specifically says they must remain accessible. My mistake, thank you for the correction.

chris75 02-11-2008 06:27 PM

Quote:

Originally Posted by Stubbie (Post 97036)
Chris

Very good catch, I was thinking there was an exception for listed pulling elbows and condelet bodies, however after checking NEC 314.29 it specifically says they must remain accessible. My mistake, thank you for the correction.


Never good when you bury a fitting... at least for the next guy...:whistling2:


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