Why must boxes be installed flush with the surface?

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George Stolz

George Stolz

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Hospital Master Electrician
What is the reasoning behind the requirement in 314.20?

I can't defend what I can't understand.

Hack work aside (I know that's generally what brings this topic to discussion), what is the safety imperative that makes this section necessary in the minimum standard?

Thanks for all replies. :)
 
Pierre C Belarge said:
Celtic
That is a good answer, simple and to the point!!!!!
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...and I just found that out like a day ago!

Seriously.

While reading some info on box adapters/extenders (because my AHJ is having a cow) - I saw this:
be1phot.jpg

I am used to using metal box adapters/extenders not plastic ones, and honestly, I thought the plastic was a bit cheap. I read something on the box to the effect of "prevents sparks" ..I don't remember exactly....put I DO remember the logic behind the phrase :D

Thanks Pierre. :)
 
georgestolz said:
What is the reasoning behind the requirement in 314.20?

I can't defend what I can't understand.

Hack work aside (I know that's generally what brings this topic to discussion), what is the safety imperative that makes this section necessary in the minimum standard?

Thanks for all replies. :)
Click to expand...

OK, I know this is a trick question, so I'll be waiting with interest to see where you take this.

One reason is to prevent the exposure of combustible materials to the interior of a box, which is also why the boxes don't have to be completely flush in a non-combustible surface like drywall.

I just purchased a bag full of these at big orange:

B1EXTB.jpg



We aren't doing any electrical work, but we are applying 1/4" pine bead board wainscoting around a room. So, I need to extend the existing boxes to fill the gap and eliminate the exposed wood.

Mike
 
georgestolz said:
What is the reasoning behind the requirement in 314.20?
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This is a flush mounted electrical box.
Drywall1.jpg



Here is an electrical box after a short circuit.
Poof1.jpg



Here is the device and plate from the above box.
Poof3.jpg




Still have questions?
 
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iwire said:
George let the other shoe drop....what have you got on your mind?
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This.
05%20Brick%20Wall%206%20x%2010'.JPG

This is always an excuse to stretch our allowed 1/4" to 1/2" or 1", and the arguments that have been presented, which I agree with in drywall, don't seem to bear the same reasoning with a block or brick wall.

A plastic spark ring will not win in a competition with a concrete block.

That's what I don't get. Thanks for all the replies, keep 'em coming. :)
 
celtic said:
A spark ring is not required on a block wall :)
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Yes, it is.

314.20 In Wall or Ceiling. In walls or ceilings with a surface of concrete, tile, gypsum, plaster, or other noncombustible material, boxes employing a flush-type cover or faceplate shall be installed so that the front edge of the box, plaster ring, extension ring, or listed extender will not be set back of the finished surface more than 6 mm ( 1/4 in.). ....
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I don't know, but I'm tempted to hop off my rock and find you some moisturizer and a plastic surgeon, because, damn, T, you need some work done! :D
 
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georgestolz said:
I don't know, but I'm tempted to hop off my rock and find you some moisturizer and an optometrist, because, damn, T, you need some work done! :D
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LMAO ....good one george :D
 
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