1-1/2" deep multi-gang electrical boxes

[Lakee911]

You're right ... the grounds are all counted once, but still multiplied by the 2cu in per conductor for #14. So that makes it 8.

I don't see how the device would be double volume allowance though. It should only be 2 for a single device, no? I'm not arguing (for once)...just trying to learn

[Chris75]

You're right ... the grounds are all counted once, but still multiplied by the 2cu in per conductor for #14. So that makes it 8.

I don't see how the device would be double volume allowance though. It should only be 2 for a single device, no? I'm not arguing (for once)...just trying to learn

if you take a look at 314.16 (B)(4) Device or Equipment Fill

For each yoke or strap containing one or more devices or equipment, a double volume allowance in accordance with Table 314.16(B) shall be made for each yoke or strap based on the largest conductor connected to a device(s) or equipment supported by that yoke or strap.

[jwelectric]

That's kind of harsh, jw. That third one does not, from all the research that I've done, exist in a 1-1/2" depth. So, I challenge you to find me one.

Didn't mean to sound harsh I meant it to sound funny.

Looking for one of those 1 1/2 inch deep go to Lowe's Home Improvement on highway 64/49 Asheboro, North Carolina and they have them by the case.

[Lakee911]

Ok then. Ha ha

Ok, so I went to bLowes, in Columbus, OH and I measured these boxes. Unfortunately, these are measured 1.5" deep from the inside and once you add the back and the plaster ring they are approximately 1-11/16 deep. Boo

So, I thought that another option would be to use a plastic 4"x4" box and sand or cut 3/16" of an inch off the face to make up for the added height. This would doable, but not ideal for more than a box or two.

I did, however, stumble upon this Raco box (http://www.myproship.com/index.aspx?...=1&sku=6228373) at Lowes. It is exactly 1.5" inches deep, on the outside, and it is gangable, if that is the correct term. A screw comes off the side and the side comes off. Multiple boxes can then be attached to eachother. You can put as many together as you would like. The plaster ears come off too to make a standard box. They're $1.98 each.

So, ok I'm good. I'm done. Thanks!

[Lakee911]

if you take a look at 314.16 (B)(4) Device or Equipment Fill

For each yoke or strap containing one or more devices or equipment, a double volume allowance in accordance with Table 314.16(B) shall be made for each yoke or strap based on the largest conductor connected to a device(s) or equipment supported by that yoke or strap.

I'm not sure I understand that, but my code book is at work. I'll look at it tomorrow. Is that 2008 or 2005?

Jason

[Chris75]

I'm not sure I understand that, but my code book is at work. I'll look at it tomorrow. Is that 2008 or 2005?

Jason

2005, its basically saying you need to add a double allowance for box fill... the number you use is based on the AWG going to the device... for example, # 14 going to a receptacle would be 4 cu., #12 would be 4.5 cu

14 awg is 2.00
12 awg is 2.25
10 awg is 2.50

[Lakee911]

Ok. I gotchya. I was misreading it over and over... thanks.

Jason

[Mikey]

I did, however, stumble upon this Raco box (http://www.myproship.com/index.aspx?...=1&sku=6228373) at Lowes. It is exactly 1.5" inches deep, on the outside, and it is gangable, if that is the correct term. A screw comes off the side and the side comes off. Multiple boxes can then be attached to eachother. You can put as many together as you would like. The plaster ears come off too to make a standard box. They're $1.98 each.

So, ok I'm good. I'm done. Thanks!

There's a minor problem with the conduit knockouts. They'll require a cable bushing, and the bushing and cable will come out of the box into the drywall. You'll have to take that into account when you cut the drywall. Other than that, they're a very useful box in this application -- you can use Tapcons to mount them directly on the block, if your AHJ will allow it.

[Lakee911]

There's a minor problem with the conduit knockouts. They'll require a cable bushing, and the bushing and cable will come out of the box into the drywall. You'll have to take that into account when you cut the drywall. Other than that, they're a very useful box in this application -- you can use Tapcons to mount them directly on the block, if your AHJ will allow it.

Hey Mikey,
I don't think that the clamps will be too much trouble. The clamps are slightly offset and that will help.

I plan on using a powder actuated fastener into the poured concrete wall--should be fun.

Thanks,
Jason

[frenchie]

If you're furring it out with just 1"... how're you going to keep your wires 1 1/4" back from the face of the framing?

Funny, there's a thread about this at JLC right now.

[Bob NH]

NEC 300.15(E) permits use of " A wiring device with integral enclosure identified for the use, . . " to be used without boxes. Such devices are not common, are more expensive than standard devices, and tend to be used in manufactured housing.

You would need to find switches and outlets that are "identified of the use" in a residence. I think finding ways to use boxes is the better solution but there is an alternative.

[Lakee911]

If you're furring it out with just 1"... how're you going to keep your wires 1 1/4" back from the face of the framing?

Funny, there's a thread about this at JLC right now.

Actually, I'm going to put on those nail protector doohickeys where they cross the framing to prevent screws from hitting the wire. I think this aleviates the 1-1/4" requirement, no?

Jason

[Chris75]

If you're furring it out with just 1"... how're you going to keep your wires 1 1/4" back from the face of the framing?

Funny, there's a thread about this at JLC right now.

You only need 1 1/4 where the wires are likely to be hit, so if he runs the wires in the middle of the bay away from the framing he is fine.

[frenchie]

Chris - So he has to go back up every time he needs to go over? How many holes is he going to wind up with in his joists?
And he has to secure the wire within 12" of any box - how's he gonna do that in the middle? Tapcons? His only option is to use plates everywhere.

For 1" of extra space in the room? Seems sort of silly...



Lakelee - instead of messing with nail protectors everywhere... why not just frame it in 2x, or better yet 1-5/8 steel studs? Leave a 1/2" free space behind, run the wires there - no worries.

[enosez]

All of this searching for the box and trying to make it work.......wouldnt it be easier and quicker to just fir out the wall and be done with it.

No cutting down boxes, no breaking block, no special order boxes.