Old Work Boxes

[Alwayslearningelec]

So I have some locations on a job where the wall are existing and we'd like to use these boxes instead of having to cut open the wall and use a 4-11/16" box with supports to the studs. I'm thinking the engineer is going to reject them as them won't offer the strength and support as using a 4-11/16 box with stud support. I'm going to write an RFI and try and make a case. Anything you can think of that may make the case to use these in the capacity they will not rip out of the wall when devices plugged into the receptacle.

 

[LarryFine]

While I haven't had that problem, you could use old-work boxes that are designed to be attached to studs.

 

[Krusscher]

I have used them with F straps and as long as you get the straps tight and no one is too rough with them they will last but I have had a few get loose and wobbly.

 

[grich]

I've also never seen a problem with metal old-work boxes, as long as the madison bars were installed properly.

 

[electrofelon]

While I haven't had that problem, you could use old-work boxes that are designed to be attached to studs.

View attachment 2566789 View attachment 2566790

I do like those boxes for NM and always try to use those on a stud. But I think the OP has MC by the sound of it and would need to use the gem boxes.

 

[LarryFine]

MC can be used with plastic boxes because of the EGC, and two can fit in one K.O.

 

[infinity]

If the walls are fire rated then attaching the box only to the Sheetrock may be an issue.

 

[electrofelon]

MC can be used with plastic boxes because of the EGC, and two can fit in one K.O.

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True, I think that would be acceptable as long as there is no instructions limiting their use to non metallic wiring methods. Fastening them to metal studs is challenging. I do tons of MC old work, and I like the metal gem boxes. I use the 3- 1/2 inch deep ones however.

 

[Alwayslearningelec]

I do like those boxes for NM and always try to use those on a stud. But I think the OP has MC by the sound of it and would need to use the gem boxes.

Correct

 

[Alwayslearningelec]

If the walls are fire rated then attaching the box only to the Sheetrock may be an issue.

Why?

 

[electrofelon]

Why?

I can't remember if it's part of the box listing that goes with its fire rating, or some other standard but somewhere it says boxes need to be secured to framing members for their fire rating

 

[infinity]

Why?

The box must be fastened to a framing memeber so that it cannot fall out during a fire.

 

[electrofelon]

The box must be fastened to a framing memeber so that it cannot fall out during a fire.

And where exactly is that requirement found?

 

[infinity]

And where exactly is that requirement found?

Here:

Metallic and Non-metallic Outlet Boxes Used in Fire-rated Assembly

iaeimagazine.org

Metallic outlet boxes for use in fire rated wall assemblies include single and double gang metallic outlet and switch boxes equipped with Listed metallic or nonmetallic cover plates. These outlet boxes are intended for installation in bearing and non-load bearing wood or steel stud gypsum wallboard walls with fire resistance ratings of 2 hours or less. The metallic outlet or switch boxes must be securely fastened to the studs. Openings in the wallboard facing are to be cut so that the clearance between the box and wallboard does not exceed 1/8 inch. The surface area of individual metallic outlet or switch boxes must not exceed 16 square inches. In addition, the entire surface area of the boxes must not exceed 100 square inches per 100 square feet of wall surface.

 

[Joethemechanic]

Personally I don't like anything that only attaches to only drywall or plaster. Maybe they weren't installed properly, or maybe rough usage. Maybe because I see too many of then used in DIY or handyman work. I just see so many of them loose and full of hackwork.

 

[winnie]

Personally I don't like anything that only attaches to only drywall or plaster.

I agree with this. Cutting the wallboard and patching is much easier than people imagine.

If you pre-make patches and cut your holes to match, it is easy put in the new box (mounted to the stud) and then seal things up. Splurge on adjustable depth mudrings and make it easy to match everything up.

-Jon

 

[Joethemechanic]

I agree with this. Cutting the wallboard and patching is much easier than people imagine.

If you pre-make patches and cut your holes to match, it is easy put in the new box (mounted to the stud) and then seal things up. Splurge on adjustable depth mudrings and make it easy to match everything up.

-Jon

Yeah people abuse receptacles a lot. Kids and pets knock corded stuff down, plugs get yanked sideways. I hate the cheepo receptacles too, they get loose quick from any kind of abuse.

 

[letgomywago]

Arlington makes a metal smart box also

 

[letgomywago]

Arlington makes a metal smart box also

Nvm it was a Canadian box not American. But you can always drill a hole and screw those gem boxes to the steel stud too. Those nema 1 boxes are a construction specification not listed so you won't need to worry about the issues that nonmetalic boxes have.

 

[Strathead]

Here:

Metallic and Non-metallic Outlet Boxes Used in Fire-rated Assembly

iaeimagazine.org

For the record, this article is an explanation (a better one) of the requirements, the actual requirement is the UL rated wall assembly, which is what specifies that the boxes must be secured to the framing.