Extension rings

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Megga Watt

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United States
I have heard this from several inspectors but can not find it in the code book.
Are we allowed to run conduit from a 4 sq extension ring?? And if not where is it in the NEC?
 

fmtjfw

Senior Member
I have heard this from several inspectors but can not find it in the code book.
Are we allowed to run conduit from a 4 sq extension ring?? And if not where is it in the NEC?

Does the ring have knock outs?
The NEC is a permissive Code.
If it is not forbidden, then it is permitted.
I know of no rule forbidding it.
 

iwire

Moderator
Staff member
Location
Massachusetts
Does the ring have knock outs?

This has a KO, can run conduit out of it?;)

51Jcr11rTTL._SY300_.jpg


The NEC is a permissive Code.
If it is not forbidden, then it is permitted.
I know of no rule forbidding it.


I agree.
 

mwm1752

Senior Member
Location
Aspen, Colo
the 4/S extensions I'm used to seeing have ko's for that purpose -- I assume the extension you are describing does not have tapped mounting screw holes for devices such as a plaster ring.
 

iwire

Moderator
Staff member
Location
Massachusetts
While running conduit out of an extension ring is legal, you must still adhere to the allowance of free conductor rule for new and existing conductors in section 300.14.



For sure, :)

It is not as restrictive as I would have thought, see what I made red. Of course the green section applies.

300.14 Length of Free Conductors at Outlets, Junctions,
and Switch Points.
At least ISO 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 lllll (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.

The green section above is why I think the subject of being able to remove the ring when needed comes up. If you hard pipe to the extension ring it is harder to remove the rings.

Personally I hate extension rings but of course use them when needed.
 

iwire

Moderator
Staff member
Location
Massachusetts
Bob, I am a bit confused. Nothing new.:)

Are you saying that an argument could be made that one could remove the ring and therefore meet the free allowance needed for an existing conductor(s)?

I am saying that is the thought process when people say you can not hard pipe into them. I am not sure where I stand on this issue.:)

My real world side tells me that extension rings are all but worthless if you have to maintain 3" out of the extension ring when attached to the box.
 

kwired

Electron manager
Location
NE Nebraska
Bob, I am a bit confused. Nothing new.:)

Are you saying that an argument could be made that one could remove the ring and therefore meet the free allowance needed for an existing conductor(s)?
Why not? It isn't much different of a task then removing the cover, unless it does have hard piped raceway connected to it.

I have many times used a 4x4 box with a 1 gang opening in the back to extend from a flush box and continue on with surface mounted raceway, not really much different than the typical extension box with a raceway attached to it.
 
For sure, :)

It is not as restrictive as I would have thought, see what I made red. Of course the green section applies.



The green section above is why I think the subject of being able to remove the ring when needed comes up. If you hard pipe to the extension ring it is harder to remove the rings.

Personally I hate extension rings but of course use them when needed.

That is when you need the extra volume of the extension ring to contain the splices to allow the pigtails that you need to add to make the extension ring compliant:angel:
 
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