Extension rings

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joeyww12000

joeyww12000

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Chatsworth GA
Seems like someone told me one time you cannot attach conduit to an extension ring? Is this correct? Ive had to get into Jboxes that have been installed this way and getting out the wire with conduits coming in the original box and the extension does make it difficult, just not sure if its a violation.
 
They have knock outs in them, why not?
I have seen so many ganged together it looked like a loaf of bread.

I had an inspector on time that didnt like ex-rings. He perfered us to chip out the column, way into the steel, and bend offsets in the conduit.
Best thing is, that it was under an airport hotel and we could only work at night. Nice thoughtful guy.
 
Sometimes they are nice if you pour a box flush in a column and need to trim it out to fit on a furred wall or behind a kitchen backsplash.
That would be good planning:rolleyes:
 
They make extensions for a reason, to extend boxes. I've heard this too about it being prohibited but I have yet to meet someone who can actually find it in the code book. :rolleyes:
 
There's no NEC prohibition on extension rings, but some projects spec them out of use.

Here's my all-time favorite extension ring pix:

boxes.jpg
 
Here's another
View attachment 2594

Extension rings are good if you have a crowded box or if you need more depth( 1 ring) in a convenient rear mounting situation(I beam).

I have never been faced with needing to use one for conduit entry.

I suppose there are reasons to use the KO s and they wouldn't be on them if they weren't intended to be used.
 
Let me play devil's advocate for a minute....314.22....


Surface extensions shall be made by mounting and mechanically securing an extension ring over the box(My comment -box and ring are singular, that means one ring per box).

Going to put my asbestos underwear on, standing by for flaming commentary.
 
The following is from the UL Guide information for Metallic Outlet Boxes (QCIT).
EXTENSION RINGS Extension rings are suitable for extending properly secured flush- or surface-mounted boxes. One or more extensions may be used. An extension ring is intended to increase the box depth, volume, or both.
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What about manufacturing your own extension rings?
Say if you have a 12x12 in the wall and need to extend it out so you cut the back out of a second 12x12 and mount it to the flush 12x12?
 
alfiesauce said:
What about manufacturing your own extension rings?
Say if you have a 12x12 in the wall and need to extend it out so you cut the back out of a second 12x12 and mount it to the flush 12x12?
Click to expand...
If I needed to, I would. I'd probably slit some rubber tubing and glue it onto the cut edges.
 
infinity said:
You would really have to work hard to convince me of a violation of that section. :rolleyes:
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Perhaps a 300.14 violation. As rings are added, all spliced or terminated conductors must extend 3" outside the opening.

300.14 Length of Free Conductors at Outlets, Junctions, and Switch Points. At least 150 mm (6 in.) of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath, shall be left at each outlet, junction, and switch point for splices or the connection of luminaires or devices. Where the opening to an outlet, junction, or switch point is less than 200 mm (8 in.) in any dimension, each conductor shall be long enough to extend at least 75 mm (3 in.) outside the opening.
Exception: Conductors that are not spliced or terminated at the outlet, junction, or switch point shall not be required to comply with 300.14.
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Smart $ said:
Perhaps a 300.14 violation. As rings are added, all spliced or terminated conductors must extend 3" outside the opening.
Click to expand...


That's a valid point but would not be a direct prohibition of using multiple collars on a box. If I need to add two collars to increase the box size for fill the fact that some conductors may be short doesn't change the fact that the box now contains the needed cubic inch area for wire fill. The way I see it those are two separate issues that must be dealt with when using collar boxes.
 
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