Advice on conduit for subpanel

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  #1  
Old 02-07-16, 09:16 AM
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Advice on conduit for subpanel

Hi!
So the main service panel is full. It's a 200A service panel. I'd like to install a sub panel on the stud right next to it (in garage)
I'll move the two 15A garage circuits to the new subpanel and install a 100A breaker for the Subpanel (bought 2awg thhn copper, and using 6awg ground) that way I can always step up to 125A if needed.

My question is: since thhn has to be in conduit, can I drill through the stud to go right into the service panel, or should I use the knockouts on the bottom and use conduit (I have 3/4" EMT but is that too small?)

Plan is to add two 14-50 outlets off the sub panel. (6awg and 8 awg ground). Yes I'm pulling permits.

Thanks!
 
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  #2  
Old 02-07-16, 09:49 AM
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Use a 1" threaded conduit nipple horizontally between the panels. Make new hole if needed.
 

Last edited by ray2047; 02-07-16 at 11:09 AM. Reason: Incorrect nipple diameter.
  #3  
Old 02-07-16, 10:15 AM
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A nipple that large will not leave much stud to carry the structural load.
 
  #4  
Old 02-07-16, 10:39 AM
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If it fits in say 3/4" nipple through the stud between panels, would that work?
 
  #5  
Old 02-07-16, 10:41 AM
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Really, Ray, 1-1/2 to 2-inch conduit? That is WAY overkill for just running between two panels in adjacent stud bays. Remember, conduit fill rules do not apply if the conduit is less than 24 inches long.

I would use a 1-inch PVC conduit as it is rated for three #2 conductors and you only need a #8 for the equipment grounding conductor. You could use a steel conduit nipple and IF you are able to use a locknut tight on both sides of the steel circuit breaker enclosures you won't even need the equipment grounding conductor.

Here's how I did it with the PVC nipple.

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I used a 3/4 inch PVC nipple with # 4 conductors (and #10 equipment ground) on an 80 ampere CB. #2 MIGHT fit in a 3/4 inch nipple with enough room for a #8 ECG, I don't know, you will have to try it.
 
  #6  
Old 02-07-16, 10:47 AM
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Nipples are allowed 60% fill max. 3 - #2 THHN and one #6 will require a 1" conduit nipple minimum.
 
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Old 02-07-16, 11:08 AM
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I will always admit when I'm wrong but I will blame my answer on plumbers who run 1" drains through studs. I have edited my post.
 
  #8  
Old 02-07-16, 12:58 PM
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Thanks guy, so I cut the drywall open...and well there's studs where I was expecting to place the sub panel.
I'm attaching a picture. To the right of the panel I penciled in the stud markings. There's double studs in the middle... (They seem to be 1.5" not 2")
There's also insulation behind the dry wall
I'm thinking of surface mounting the panel to the studs, and running the conduit through the back kickoff. (I don't think cutting the studs on a load bearing wall is code....haha)
Thoughts? Thanks!

https://goo.gl/photos/jcFmYniVhVUhFWK98

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Last edited by PJmax; 02-07-16 at 01:16 PM. Reason: added pic from link
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Old 02-07-16, 01:14 PM
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We don't really need to see in the panel better. His problem is studding in the wall.
 
  #10  
Old 02-07-16, 01:37 PM
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Can I drop the panel right below the main? I could flush mount it in the wall. Then I can run pvc conduit to the right of the main panel for my 14-50 outlet.
Only thing is moving the main breakers to the sub, can I use wire caps to extend the 4 wires to make space for the sub feed?

https://goo.gl/photos/gRQQ9GEWoX2MLwzH9

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Last edited by PJmax; 02-07-16 at 01:41 PM. Reason: added pic from link
  #11  
Old 02-07-16, 01:44 PM
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I don't know..... I wouldn't want a panel that low to the floor. You couldn't put anything in front of it. Personally, I'd reframe the wall if it was me.

Only thing is moving the main breakers to the sub, can I use wire caps to extend the 4 wires to make space for the sub feed?
I think you worded that wrong. The main breaker stays in the main panel. Did you mean to ask if you can extend a circuit or two to the new sub panel by using wire nuts..... that would be a yes.
 
  #12  
Old 02-07-16, 01:49 PM
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Thanks!
Yes I meant extend the wires I'm moving to the sub.
So which way is better? Flush mount below (nothing would ever go in front of that, we have a large 3 car garage) or surface mount next to it?
Is there any code specifying how far off the ground it has to be?
Thanks again!
 
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Old 02-07-16, 02:41 PM
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Just a thought. The two studs side by side would offer a good place to surface mount a box and you could come into it from the back with cables from the bottom of the existing flush mounted box. No conduit needed. Just mount the new box so about three inches of it is to the left of the stud pair so easy access to the back.
 
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Old 02-07-16, 04:36 PM
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I would nipple another panel under the first panel.
 
  #15  
Old 02-07-16, 06:18 PM
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Thanks guys, hoping I can wrap this project up over the next week or so, I'll post pics when done!
 
  #16  
Old 02-09-16, 06:44 AM
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Ok so I took out the section below the service panel for the sub panel to go...nothing is ever easy apparently.

There's 3 wires traversing the studs where I want to put the subpanel. two wires come from the left and right through the studs and go into the bottom of the service panel. Easy enough to route them through the sub into conduit into the service panel.

One wire just runs horizontally through the studs, I have no idea where this wire goes. Is it to code to cut this wire, and place my subpanel and then use wire caps to reconnect it through the subpanel? (just use side kickouts, and run it around the bottom then back out to the right?)

Or I can cut out more drywall and move the subpanel lower without re-routing any wires, but the panel will be literally a few inches from the ground with a 18" gap of drywall between the panels.

Thoughts? (Pics when I get home tonight)
 
  #17  
Old 02-09-16, 06:12 PM
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You didn't say how many more circuits you needed They do make thinner panels instead of the standard 14.5" load centers. Here is one example:

Eaton 100 Amp 10-Space 20-Circuit Surface-Cover Main Breaker Indoor Load Center-BR1020B100S11 - The Home Depot

Or

http://www.homedepot.com/p/Square-D-...0FCP/100149777

How much space do you have to the left of the studs or even to the right of the studs?
 
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