344.30 supporting T condulets

[jaggedben]

Conduit bodies have no means to attach them to anything. How would one mount it to the structure drill holes in it?

Looking again, the exception appears to apply only to the 100 cubic inches restriction. i.e. a box over 100 cubic inches cannot be supported by conduit, but a conduit body can. Apparently you need a 2.5" conduit body before this even becomes an issue.

 

[Isaiah]

Looking again, the exception appears to apply only to the 100 cubic inches restriction. i.e. a box over 100 cubic inches cannot be supported by conduit, but a conduit body can. Apparently you need a 2.5" conduit body before this even becomes an issue.

So going back to post #15; do we need to support a T fitting with 3 conduit entries on all three sides AND within 3’?(no reducers)


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[jaggedben]

So going back to post #15; do we need to support a T fitting with 3 conduit entries on all three sides AND within 3’?(no reducers)

Yes. (Reducers or not.)

(If any of the three conduits are short, straight nipples going right into another box or piece of equipment that's attached to the structure, pretty much everyone lets this slide.)

 

[ActionDave]

So going back to post #15; do we need to support a T fitting with 3 conduit entries on all three sides AND within 3’?(no reducers)


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This is what I was referring to in your OP. You don't need to support the T. You do need to secure the conduits going into the T

344.30 Securing and Supporting

RMC shall be installed as a complete system in accordance with 300.18 and shall be securely fastened in place and supported in accordance with 344.30(A) and (B)

(A) Securely Fastened
RMC shall be secured in accordance with one of the following:
RMC shall be securely fastened within 900 mm (3 ft) of each outlet box, junction box, device box, cabinet, conduit body, or other conduit termination.

 

[Isaiah]

Yes. (Reducers or not.)

(If any of the three conduits are short, straight nipples going right into another box or piece of equipment that's attached to the structure, pretty much everyone lets this slide.)

Makes sense - thank you very much


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[garbo]

Side note: Years ago it was fairly easy to install supports within 3' of " T " condulets when in most small to medium buildings bar joist were less then 10' apart so a 10' piece of unistrut could be installed to provide needed support. Recently while in one of the big box stores I was checking out conduit runs below the ceiling. They used fairly large trusses guessing at least 20' from next one. Never drilled holes in steel corrugated roofs for fear of creating leaks even with sealant and the screws with thick rubber gasket like the type used on AC units.

 

[Isaiah]

Side note: Years ago it was fairly easy to install supports within 3' of " T " condulets when in most small to medium buildings bar joist were less then 10' apart so a 10' piece of unistrut could be installed to provide needed support. Recently while in one of the big box stores I was checking out conduit runs below the ceiling. They used fairly large trusses guessing at least 20' from next one. Never drilled holes in steel corrugated roofs for fear of creating leaks even with sealant and the screws with thick rubber gasket like the type used on AC units.

Not good. Makes you wonder how did this pass inspection?


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[Dale001289]

Yes. (Reducers or not.)

(If any of the three conduits are short, straight nipples going right into another box or piece of equipment that's attached to the structure, pretty much everyone lets this slide.)

314.23(E) states if you have raceway entering not more than 300cu inches enclosure (e.g. 4" conduit Tee fitting), the Tee can be supported via the exception as long as two or more conduits that can be threaded into hubs on the Tee - the Tee must same trade size as the largest conduit entry. For example a 2" Tee with a 2" RMC conduit on one side needs only to be supported once, within 3'-5'. There is no need to support the Tee on all three sides within 3'-5'. 344.30(B) would then apply in other words the 2" RMC could be supported at 16'.

 

[jaggedben]

Yes but each run of conduit must be supported within 3ft of the box or conduit body. Period. Regardless of what it's going into. It's a requirement to support the conduit, not the conduit body. And there are no exceptions.

I'll add one clarification: if not all three entries of the tee are used and one is just plugged, then supporting the tee with only two conduits is fine.

Looking back, the way the question is phrased is actually moot and misleading and has led to an unnecessarily long thread. Do you have to support the Tee on all three sides? Who cares!? You have to support the conduit anyway, regardless of what it's entering.

 

[Dale001289]

The OP question is completely legitimate and the only reason the thread is so long is because 314.23 is very poorly written, which has led to mass confusion on how to support conduit when a condulet is involved. I believe only one support is needed via the exception.

 

[jaggedben]

... I believe only one support is needed via the exception.

You're incorrect. Unless only one entry is used.

 

[Isaiah]

314.23(E) states if you have raceway entering not more than 300cu inches enclosure (e.g. 4" conduit Tee fitting), the Tee can be supported via the exception as long as two or more conduits that can be threaded into hubs on the Tee - the Tee must same trade size as the largest conduit entry. For example a 2" Tee with a 2" RMC conduit on one side needs only to be supported once, within 3'-5'. There is no need to support the Tee on all three sides within 3'-5'. 344.30(B) would then apply in other words the 2" RMC could be supported at 16'.

This seems to be the lowest cost option.
I will present all interpretations to the AHJ and see what he says


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[jaggedben]

At this point I've gotta wonder why it even came up. Are you putting two luminares in a Tee?