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

Chris75 · Jan 14, 2008

Lakee911 said:
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 · Jan 15, 2008

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

Jason

Sponsor · 2022-01-29T12:20:58-0800

Mikey · Jan 15, 2008

Lakee911 said:
I did, however, stumble upon this Raco box (http://www.myproship.com/index.aspx...38bfb9907b33d920d4&tab=13&Qtype=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 · Jan 15, 2008

Mikey said:
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 · Jan 15, 2008

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 · Jan 15, 2008

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 · Jan 15, 2008

frenchie said:
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 · Jan 15, 2008

frenchie said:
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 · Jan 15, 2008

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 · Jan 16, 2008

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.

Lakee911 · Jan 16, 2008

enosez said:
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.

No in this case it wouldn't be easier. I already have the 1" lumber (5/4 deck boards) on location because it was left over from another project. Since its treated I don't have anything else to do with it. Besides, then I'd have to buy more 2x material.

If you had read the rest of the thread you would see that I'm not cutting down boxes, I have poured concrete walls that I'm not cutting or breaking and the boxes that I chose are available in stock from bLowes.

Jason

Chris75 · Jan 16, 2008

frenchie said:
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...

His boxes are not big enough for two wires anyways, so whats the big deal and yes tapcons and tyraps with a hole would work just fine... nail plates are one way, but just not the way I would do it... too many guys would just pre dill if they felt resistance anyways...

Frenchie · Jan 16, 2008

Chris75 said:
His boxes are not big enough for two wires anyways

Didn't think of that.

Lakee911 said:
No in this case it wouldn't be easier. I already have the 1" lumber (5/4 deck boards) on location because it was left over from another project.

Or that.

Enosez · Jan 18, 2008

Lakee911 said:
That first link won't look very nice in a finished basement. The second link doesn't work and the third is 2" thick.

Any other ideas?

I'm afraid I'll have to chip out the concrete behind a 2" device.

Thanks,
Jason

My error, instead of block, you meant "chip concrete"...

Either way, still sounds like a lot of work.

If you have the 5/4 left over, double them up, tripple them up. Still less work than chipping block, oh I mean concrete

Mikey · Jan 18, 2008

Run single cables into the boxes and terminate them in junction boxes above the ceiling. Interconnect everything in the junction boxes, which you can make as big as you want. Only hitch is the junction boxes have to be accessible; you could put them anywhere -- "above the ceiling" just seemed easiest, but if they're not accessible there, put them somewhere where they are.

One other thing to remember: if you're mounting a box like this on a hard surface at the back, drill a clearance hole for the grounding screw. Especially important to remember if you're using a powder-driven fastener to mount the box.

Lakee911 · Jan 18, 2008

Thanks, Mikey. I didn't think of that. These boxes do not have the raised little bump for the screw clearance. Can I bond the box by shooting a fastener with a washer over a loop of ground wire?

Thx
Jason

Mikey · Jan 18, 2008

I doubt it, since they even require green screws these days (apparently signifying Code-approved). I'm sure somebody can come up with the Code reference.

Chris75 · Jan 18, 2008

Mikey said:
I doubt it, since they even require green screws these days (apparently signifying Code-approved). I'm sure somebody can come up with the Code reference.

They do not have to be green...

Mikey · Jan 19, 2008

That day will come...

250.126 requires green screws with a hex head for EGCs, or a green nut, or a green pressure wire connector. on wiring devices. 250.8 prohibits sheet metal screws for connecting grounding conductors to enclosures, but (you're right) doesn't say what is required. 250.148 says "grounding screw that shall be used for no other purpose". There may be other advice scattered in the Code, and all this is based on the 2005 Code -- don't know what 2008 (or your local AHJ) says.

Nice long thread about this on Mike Holt's forum: http://forums.mikeholt.com/showthread.php?t=76912

I used to use one of the clamp screws in a box (after removing the clamp) but a local Master Electrician who advises me said that wouldn't be acceptable to our AHJ. An electrician in Pittsburgh says his AJH requires the green screws.

Bottom line -- if you use the green screws (which, BTW, one of Mike Holt's posters said weren't Listed) you'll pass. If you don't, you might not.

Lakee911 · Jan 19, 2008

Thanks. I'll go with a green screw.

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

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