Box Supports

[Robert Ellenberg]

E3806.8.2.1 Nails and screws, where it discusses first brackets and then "or they shall pass through the interior within 1/4" of the back or ends of the enclosure". Some of the steel boxes have holes in the sides close to the front or open side of the box, where a screws or nails can be used to attach it to a stud. They have to be slightly angled but they do not pass "through" the box. Is this permissable? I know they section of the code was rewritten in 2006 but I think the revision had to do with not having screw threads inside the box.

 

[Bryan Holland]

No. Those holes are not intended to be used for mounting screws or nails. Unless the box is designed, identified, and listed with means to attach the box with screws within the enclosure of the box, screws and nails must be on the outside.

 

[chris kennedy]

E3806.8.2.1 Nails and screws, where it discusses first brackets and then "or they shall pass through the interior within 1/4" of the back or ends of the enclosure". Some of the steel boxes have holes in the sides close to the front or open side of the box, where a screws or nails can be used to attach it to a stud. They have to be slightly angled but they do not pass "through" the box. Is this permissable? I know they section of the code was rewritten in 2006 but I think the revision had to do with not having screw threads inside the box.

No. Those holes are not intended to be used for mounting screws or nails.

Really? I would have to wonder what they are for.

314.23(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 (¼ 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.

Are the ends of the box not the sides? If not, can you tell me where the "ends" of the box are?

Unless the box is designed, identified, and listed with means to attach the box with screws within the enclosure of the box, screws and nails must be on the outside.

Help me with this one, it is my understanding that only boxes used in wet or damp locations need to be listed as per 314.15. How does that apply to a 4" square?

 

[Robert Ellenberg]

I am with Chris, what are they for? I was under the impression that the language regarding passing "through" the box being close to the back was to specify that long nails or screws going through one side and then the other had to be all the way to the back where they did not interfere with the wiring. Screws or nails installed from the front inside edge make no interference what so ever and there is no other possible use for them.

 

[Bryan Holland]

The end of the box is the same as the back of the box. Saying the "back or end of the box" is the same as saying the "top or peak of a mountain." That is, the box ends at the back of the enclosure.

4" square boxes are a type designed with mounting holes in the side. Not all steel boxes have holes for this purpose.

 

[chris kennedy]

Ahh gotcha, I just assumed we where talking 4"square (painfully again). A handy box or concrete box would be what you were talking about, in that case I would agree.

 

[globe trekker]

You guys have any pictures to share with the class?

Pictures are always a good learning tool!

.

 

[Robert Ellenberg]

This Steel City cataloge page shows several examples. I tried to embed it but lost too much resolution so you'll need to open the zip.Bryan--please comment. Your 2nd post indicates there are boxes such as these where the nail can enter from the inside near the front edge and when fully in place, only the head would be inside the box. This would seem to be similar to placing a screw straight through the back of a box where you fasten it to a surface behind the box since when it is fully in place only the head remains within the box.

View attachment 219

Steel City Elec Boxes zip.zip

Steel City Elec Boxes zip.zip