Box extensions and risers

[steve holt]

I know that there is/was a code limiting the number of extensions or risers that you can install on a box but cannot find it. Is it still there or has this been eliminated?

 

[480sparky]

I don't recall there ever being one.

 

[celtic]

300.14 might be the closest you will find.

 

[kkwong]

Possibly manufacturer's instructions, but that's pushing it...

 

[480sparky]

I prefer making sandwiches with them. :grin::grin:

 

[celtic]

Possibly manufacturer's instructions, but that's pushing it...

I don't recall ever seeing instructions on an extension ring....this was brought up before in regards to a post of mine:
Violation or not ???

08-01-2007...rambled on for about 5 pages.

 

[infinity]

I hear a lot of misinformation regarding extension collars. Guys have told me that you can only use one. Another guy told me that they're "technically" illegal since the box should have been sized properly in the first place. Another one that I've heard, you can use an extension collar but you're prohibited from using any of the KO's in them. I often wonder who makes up this stuff.

 

[daleuger]

I hear a lot of misinformation regarding extension collars. Guys have told me that you can only use one. Another guy told me that they're "technically" illegal since the box should have been sized properly in the first place. Another one that I've heard, you can use an extension collar but you're prohibited from using any of the KO's in them. I often wonder who makes up this stuff.

I've heard that too. I've also heard that you can use them to your heart's content as long as you don't leave any open KO's.

Edit to add: Why would they have KO's in them if they weren't intended to be used?

 

[luckyshadow]

There is no rule in the nec as to how many extension rings(boxes) may be installed on a box. There is no rule about piping out of an extension.
The place where you get into trouble is the length of free conductors in that box. If the opening in your box is less then 8" in any direction, you must have at least 3" of free conductor outside the box opening.
Article 300.14 - 2008 NEC

 

[walkerj]

You can put as many as you want, but good luck with more than two if you're pulling wire in
http://forums.mikeholt.com/attachment.php?attachmentid=2594&d=1228605582

 

[LarryFine]

You can put as many as you want, but good luck with more than two if you're pulling wire in
http://forums.mikeholt.com/attachment.php?attachmentid=2594&d=1228605582

You'll notice in that picture that both MA's have notches worn in them from the fishtape, too.

 

[walkerj]

You'll notice in that picture that both MA's have notches worn in them from the fishtape, too.

Yea, I noticed because I put them there
The one with the fish tape in it never made it out or in all the way in

You'll also notice a wasp nest

 

[Karl H]

I prefer making sandwiches with them. :grin::grin:

This is my favorite picture of "The Many Ways to Increase Your Volume
of a Box, if you have no business doing electrical work in any shape or form."