Do I need to extend my electrical boxes

[Mainiac Mat]

Truss framed ceiling with 3/4 strapping and 5/8 fire rated drywall....

I mounted my blue poly light boxes as low as I could go on the bottom cord of the truss.

They do not extend fully to the bottom of the hole in the drywall... leave about 1/4" to 3/8" of the drywall holes showing.

Is this not big deal?

Or do I need to put an extension on the boxes?

If extension is required, do they even make them for the blue poly boxes?

Thanks in advance for any tips.

 

[Terry D]

Article 370-20 states they can set back no more than 1/4" from the finish surface. I don't understand why you could not have brought them down more, plus they make adjustable boxes. They do make box extensions for the blue boxes. It is a code violation if they set back more. its up to you if you want to use extensions or not.


https://www.lowes.com/pd/CARLON-Blu...dard-Box-Extender-Wall-Electrical-Box/4411965

 

[pattenp]

1/4" is the max allowed by the NEC that the front edge of the box can be back from the drywall finished surface.

 

[Mainiac Mat]

Thanks for the help.

I bought the standard (inexpensive) Carlin blue 4" diameter boxes and nailed them as close to the bottom of the truss as I could get... which (unbeknownst to me at the time) doesn't span the 1-3/8" needed to bridge both the strapping and sheet rock.




I didn't mount the boxes to the strapping because the attic deck is already in, so I had to install insulation from the bottom (staple up kraft faced fiberglass) and it's a lot easier to put that in before the strapping.... but rough wiring had to be done before the insulation....

Once I got the strapping up I could see that the boxes were going to be high... and sure enough, now that I have half of the rock up... there's a gap.

Seems like a non-issue and I've already had my rough wiring inspection... not sure if I'll just use as is, or get the Carlon extensions.

 

[Terry D]

Thanks for the help.

I bought the standard (inexpensive) Carlin blue 4" diameter boxes and nailed them as close to the bottom of the truss as I could get... which (unbeknownst to me at the time) doesn't span the 1-3/8" needed to bridge both the strapping and sheet rock.




I didn't mount the boxes to the strapping because the attic deck is already in, so I had to install insulation from the bottom (staple up kraft faced fiberglass) and it's a lot easier to put that in before the strapping.... but rough wiring had to be done before the insulation....

Once I got the strapping up I could see that the boxes were going to be high... and sure enough, now that I have half of the rock up... there's a gap.

Seems like a non-issue and I've already had my rough wiring inspection... not sure if I'll just use as is, or get the Carlon extensions.

What I linked was for device boxes, I would imagine they would make a extender for round plastic as well

 

[Mainiac Mat]

This is the product Carlon makes.... they call it a "Plaster Ring" and it steps down from 4" dia. to 3" dia. and they come with either a 1/2" step or a 5/8" step.



Looks like a workable option....

 

[Bert_]

Arlington makes box extenders for device boxes and octagon.

http://www.aifittings.com/catalog/miscellaneous/box-extenders/

 

[66cj225]

Fire rated drywall and plastic boxes- what could go wrong?

 

[Mainiac Mat]

Fire rated drywall and plastic boxes- what could go wrong?

 

[Mainiac Mat]

You had me scared there for a minute....

Though not ideal, it appears that I'm code compliant...

 

[66cj225]

Thanks for the info, I was just guessing. Now I'm going to toss a blue box in the wood stove for chuckles.

 

[66cj225]

The box that went into the stove had a UL BH122 and kind of a glass mat finish. It didn't support combustion but became a totally different shape by melting (blob) within 5 minutes.

 

[Mainiac Mat]

The box that went into the stove had a UL BH122 and kind of a glass mat finish. It didn't support combustion but became a totally different shape by melting (blob) within 5 minutes.

Not exactly UL or ASTM testing standards... but a little unsettling just the same. But if you have that type of intense fire, I think you're screwed regardless.

 

[mobetta]

Yeah i think its pretty funny that I had to make a "firewall"(5/8 gyp both sides to roof deck) on my lot line wall but theres is absolutely no care given to the wiring/boxes/penetrations on that wall.

I did use putty pads on my PVC outlet boxes but NOT NEEDED....