Only so much can go in a box, and each device counts so much towards the cubic inches inside of a box. Does anybody know how to count NEMA plugs towards this total? Last week I was in a Home Depot, and the, ahem..., isle "expert" assured me that I could put a NEMA 6-30R in a single gang box.

Basically, I put this:



into this:



There is nothing else in the box save the 10-2 incoming wire. I was able to make it fit, but damn, it was tight. Does this make the box overcrowded in the code, or am I ok?

Not an electrician, but ISTR the retail packaging for receptacles and boxes had this information printed on them.

Code aside, will it even fit? lol

I've changed about half a dozen dryer outlets in my life, and about sixhundred-ninetyfive-jillion stove outlets, and none of them were in a single gang box. If that means anything. It might not. Dunno. lol

It fit, but there was no spare room. It was one of those change of plans deal. It was originally going to be a 120v outlet, then after the wall was finished, I realized the heater that I really wanted was 240v.

I don't know exactly what the code is, but minimum for me would be a 4x4x2 with a single gang mudplate.

Apparently Leviton makes a cover plate for it...Leviton 84028 1-Gang Flush Mount 2.15-Inch Diameter, Device Receptacle Wallplate, Device Mount, Stainless Steel

https://www.amazon.com/Leviton...inless/dp/B000FK9X6W

Regardless, I'd DEFINITELY mount that receptacle in a 4x4x2 box!

If you wind up changing out the box THESE are great

I put a 6-50R with 6-2 in a single gang box. It was tight, but a shipping crate would have been a PITA with 6ga. Don't know if it's code, but it isn't an issue. I just don't have a ton of extra wire. It's directly below the panel, facing opposite in the wall, maybe 4ft of wire for the run.

Box fill calc:

#10 = 2.5 cu in.

2 x 2.5 conductors
1 x 2.5 ground
1 x 2.5 clamp
1 x 2.5 yoke
1 x 2.5 device

Total = 15 cu in box.

Check box for stamped rating on box. That box is likely 14.5 cu in box and is likely a code violation. Even if not (deeper than 2.5" box depth) I'd never cram the wires in there due to bending radius, heat dissipation, and ease of install.

The side mount box posted above may work. I'd use an Arlington F102 Box .

PS if you used that side mount metal box, they are nearly impossible to remove without drywall damage. So if I was doing it, I'd probably use an old work box with flappers and use a sawzall to cut box from side mount (portion screwed to stud) then cut 2g box in. I can do it with 90% chance of no drywall damage, for someone who hasn't done it hundreds of times it's 50/50 you'll have drywall damage. Also you may have to move outlet up/down 1/2-3/4" depending on slack and how far back wire was stripped. I'd recommend having an electrician do it. Worth a $150 service call just do to the likelihood of drywall damage being much smaller with a good electrician.

PPS a 4" depth box will only work with 2x4 construction, if you have 2x3 it will have to be a 2g box, and not the F102 mentioned above.

Thanks for the calculations Skins. It's difficult to want to remodel the day after you cleaned your last paint brush from the job. Literally, I just finished up yesterday, and then decided that a 220v service would be necessary.

This receptacle is ceiling mounted. It doesn't need to be flush. Maybe I could pick up the little bit of extra room I need by adding an extension? Or perhaps after I buy the heater, I can just eliminate the plug completely and do a hard wire install. Maybe that would be best.

I do have access to the backside. The backside is in the attic.

quote:

Originally posted by sigcrazy7:
Thanks for the calculations Skins. ...

I do have access to the backside. The backside is in the attic.

I miscalculated, yoke is 2x wire volume, so you are way undersized. It's been too long since I've had to do calcs.

Definitely replace box since you have attic access.

If your existing single gang box is flush against an attic floor joist and you don't want to have to make a new hole, they make an offset single gang mudplate you can still put on a 4x4x2 which should let you use your existing hole after removing the original box.