Installing device boxes in new and rework

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kd6kyy

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Article 314.23 of the 2008 NEC talks about nails or screws passing through the interior of the box within a 1/4 inch of the back of the box. Does this mean for example that it is not permitted to drive drywall screws through the side of a plastic device box into the stud to hold it in place? It is my thought the only permitted way to do this is with a box specifically made with screw pockets in side or directly through the back where screw holes are provided. (IE smart box) If some one has a clear understanding of this issue it would be greatly appreciated. Mark.
 
Didn't we just discuss this ? I'll check, hold on.


Okay before we we're talking a 4" sq boxPlastic is a different ball game.

It must be used as it was designed and UL approoved. Some inspectors are afraid the srew will come loose and some how energize the wood. :)
 
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kd6kyy said:
Article 314.23 of the 2008 NEC talks about nails or screws passing through the interior of the box within a 1/4 inch of the back of the box. Does this mean for example that it is not permitted to drive drywall screws through the side of a plastic device box into the stud to hold it in place? It is my thought the only permitted way to do this is with a box specifically made with screw pockets in side or directly through the back where screw holes are provided. (IE smart box) If some one has a clear understanding of this issue it would be greatly appreciated. Mark.
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In my opinion if the nail or screw passes thru the box then the screw head needs to b protected from contact with conductors in the box. Smart boxes by Arlington have a recess area that the screw heads go into to avoid this issue.

SBCMM1G.jpg
 
Here is a reference

314.23 Supports.
Enclosures within the scope of this article shall be supported in accordance with one or more of the provisions in 314.23(A) through (H).
(B)(1) Nails and Screws. Nails and screws, where used as a fastening means, shall be attached by using brackets on the outside of the enclosure, or they shall pass through the interior within 6 mm (? in.) of the back or ends of the enclosure. Screws shall not be permitted to pass through the box unless exposed threads in the box are protected using approved means to avoid abrasion of conductor insulation.
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This is for metal boxes or plastic boxes IMO.
 
believe it or not, a certain city on the coast here in Texas allows e.c.'s to take a nail on box, cut the nail and "fingers" that hold nail in place off of the box, insert in cutout, and install sheetrock screws through box and into 1" pine shiplap to hold in place. this was before the smartbox and on the coast in houses over 100+ years old with walls that are open to salt air, this was common practice. using a steel gangable box with ears was the "nec approved method" however 6 months later, the screws would shear off at the yoke due to corrosion, so this is why it became common practice. i only did this while i was an apprentice, when i became a j-man, i installed boxes with ears and used small wood screws to secure box to shiplap. and no old work box made has a screw and wing long enough to hold box to a 1 1/2" substrate.....not that i know of anyway.
 
quinn77 said:
believe it or not, a certain city on the coast here in Texas allows e.c.'s to take a nail on box, cut the nail and "fingers" that hold nail in place off of the box, insert in cutout, and install sheetrock screws through box and into 1" pine shiplap to hold in place. this was before the smartbox and on the coast in houses over 100+ years old with walls that are open to salt air, this was common practice. using a steel gangable box with ears was the "nec approved method" however 6 months later, the screws would shear off at the yoke due to corrosion, so this is why it became common practice. i only did this while i was an apprentice, when i became a j-man, i installed boxes with ears and used small wood screws to secure box to shiplap. and no old work box made has a screw and wing long enough to hold box to a 1 1/2" substrate.....not that i know of anyway.
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You need to use double dipped hot galvanized screws, for real.

Had a freind build a deck at the coast . He used all galvanized screws.
No good the inspector says they need to be double dipped hot galvanized screws. This was a $30.000 deck. So he says sure I'll just add more screws. The HO wanted it done over. Ouchhh!
 
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