"Getting out of the wall" for surface installation

[e34 brian]

I'm all set to start my surface installation of lights & outlets, tapping into the existing flush-mounted light and plug. My one issue is what exactly code allows when I mount a surface box on top of the existing flush-mounted box.

I know to use a box extender, but here's the rub. The existing boxes are mounted flush with the inside edge of the drywall. I'd like to mount a box extender to the outside edge of the drywall, pull the wires into the new box, and go on with my install. I can't find anything on if it is OK to sandwich drywall between 2 boxes, or if the extension has to have some sort of metal sheath between the 2 boxes to protect the drywall. It seems safe, but I don't know if it's 'proper.'

Any know about this or know which codes I could re-review?

 

[rockwithjason]

use a spark ring (sometimes called a goof ring)between the extension box and the wall mount box. this will solve the problem cheap and easy

http://www.kyleswitchplates.com/plastic-box-extender-goof-ring-adjusts-up-to-1-5-deep-1-gang/

 

[Aceman]

This is how I'd do it.

 

[53Sparky]

This is how I'd do it.

That would be a code violation without the spark ring that rockwithjason suggested.

 

[e34 brian]

Wow, I've been surfing here and reading for 2 days and didn't figure this out myself. THANKS Ace, Sparky, Jason. You answered all 3 of my questions. What needs done, how, and if it's required by code.

Now to go find that square 4" with a cutout for the plastic goof ring. Amazon to the rescue.

 

[Stuff]

You don't want to mix metal and plastic.
https://www.amazon.com/dp/B00PSMWOQS/?tag=atomicindus08-20

 

[Aceman]

That would be a code violation without the spark ring that rockwithjason suggested.

The spark shield was in the second attachment in my post....

You don't want to mix metal and plastic.
https://www.amazon.com/dp/B00PSMWOQS/?tag=atomicindus08-20

Why?

 

[Stuff]

Why?

1st - it violates UL listings and some people are sticklers
2nd - All metal parts need to be bonded to ground and the plastic pieces make it difficult.

 

[zmaxmotorsports]

Why are your boxes installed flush with inside of sheetrock?

 

[Norcal]

1st - it violates UL listings and some people are sticklers
2nd - All metal parts need to be bonded to ground and the plastic pieces make it difficult.

How does it violate the UL listing?

A plastic extension is not going to make any difference bonding parts together, the only connection will be the screws between the box & the surface extension.

 

[prostreetamx]

All my boxes are already plastic and if I needed an arc shield they would also be plastic. Have had issues with the metal ones hitting the side screws. If you use a metall 4/0 extension ring and conduit all you need to do is ground that part with a clip or screwed on green tail from your existing ground. The arc shields would be sandwiched between the original box and the new extension since they have a flange that fits around the screws and sits on the wall surface. do not rely on the device screws to provide a reliable ground, even if the original boxes are metal. Even with metal boxes, receptacles still need an attached ground unless they have the extra tang around the screw that provides a ground path. Even then I would use a ground wire on the receptacle. We use those 20a plugs on everything for doing Trade Show electric and bad grounds are a very common issue when the extra tab wears out or the screws loosen up from the constant use and storage of our equipment.

 

[Stuff]

I always thought that metal mud rings and extensions were not listed to use with plastic boxes just like MC cable isn't listed. Grounding with a clip makes sense.

 

[e34 brian]

Why are your boxes installed flush with inside of sheetrock?

I'm not sure. I'd have to ask the contractor that did it in 1978. It may have to do w/ it being a light fixture.

 

[zmaxmotorsports]

I always thought that metal mud rings and extensions were not listed to use with plastic boxes just like MC cable isn't listed. Grounding with a clip makes sense.

They make 2 gang fiberglass boxes that are made to have metal plaster rings to make them either 2g or single gang depending on what you need.

 

[CNGsaves]

Cut a 6" wide strip out of sheetrock around the shop and "go to town" installing all the electrical improvements that you want/need.

Fishtape the wire up or down from the cutout in the sheetrock for outlet placement. Don't forget outlet up in ceiling for your hanging electrical reel !!

Then patch & re-mud the sheetrock when everything is done.

 

[zmaxmotorsports]

Cut a 6" wide strip out of sheetrock around the shop and "go to town" installing all the electrical improvements that you want/need.

Fishtape the wire up or down from the cutout in the sheetrock for outlet placement. Don't forget outlet up in ceiling for your hanging electrical reel !!

Then patch & re-mud the sheetrock when everything is done.

 

[e34 brian]

Yep. Definitely doing the improvements.Personal preference, I'm sick of drywall for this year. Conduit appeals to my inner 10-year old with tinker toys self. Thinking of running another circuit from the breaker box and then wiring 2-gang boxes, 1 gang 15A, 1 gang 20A. But then I start thinking I may want to get into welding and a 50A would be nice. And so it goes.

Look what this forum is doing to me!

 

[e34 brian]

Can any of you code-savvy folks direct me to the codes that address this? I'd like to read up on this and understand exactly what I need to install. Again, the original builder mounted my electrical box on the inside edge of the drywall and I want to put a box on the outside edge of the drywall.

The extension ring we talked about earlier is a 1-gang size and it seems weird to me that I can run my wires through that and ignore the gaps left outside of the 1-gang extension. (Amazon link). I'm also wondering if I can simply mount that extension ring to the outside edge of the drywall, mount a normal box on top of that and run my wires through the extension ring and into a punchout on the bottom of the new box.

Whatever I end up learning/doing, I'm definitely going to post a step-by-step of the install with pictures. I doubt I'm the only one w/ this problem.