J box supported by emt 3/4" is it legal in 2023?

[brother]

Saw some floating boxes and had a discussion with a co worker. They claimed that the new code says you can support basic 4 square boxes with 3/4" EMT. I have not found this, but I want to be sure there is not a change that I am not aware of.

Last I recall the boxes have to have threaded entries and/or hubs and IMC or RMC (which is threaded) can support them from different sides when strapped within in 3ft. 18" if the same side. Has this changed?? Emt can support conduit bodies, LB LL OR pull C's but not boxes.

Let me know If I am missing something. Below is a pictures of what we were looking at.

 

[hbiss]

The "new" code changes nothing about that. Put something behind that box with some screws through the holes in the back of the box into the steel.

-Hal

 

[infinity]

How do you know that it's not attached to the steel?

 

[brother]

How do you know that it's not attached to the steel?

We had a lift and had a closer look. it is raised off of the steel and box is just floating.
I thought the pictures showed that.

 

[infinity]

We had a lift and had a closer look. it is raised off of the steel and box is just floating.
I thought the pictures showed that.

Sorry i was looking on my phone and the photos are a little blurry. Looking again yes, to answer your question the box needs to be attached to something other than the three raceway entries.

 

[don_resqcapt19]

While a common practice in some areas, the code has never permitted EMT to support a box

 

[brother]

While a common practice in some areas, the code has never permitted EMT to support a box

I wonder why? having three 3/4" emt conduits from different directions and strapped within 3ft to support a small 4 square box is mechanically sound in my opinion. Does anyone know the history of this box support article from conduits?

 

[Eddie702]

I wonder why? having three 3/4" emt conduits from different directions and strapped within 3ft to support a small 4 square box is mechanically sound in my opinion. Does anyone know the history of this box support article from conduits?

I agree.
I don't feel like a box supported by Rigid or IMC is any more secure than EMT.

It's all a matter of workmanship.

 

[don_resqcapt19]

I agree.
I don't feel like a box supported by Rigid or IMC is any more secure than EMT.

It's all a matter of workmanship.

I think it is a matter of threads into a threaded opening on the the box vs locknuts on an EMT connector. While not likely, it is possible the locknuts will work loose, but with two conduits into threaded entries those connections cannot come loose.
Note that it is my opinion that the code rule permitting conduits to support a box, requires that the box itself have threaded openings.

 

[letgomywago]

I think it is a matter of threads into a threaded opening on the the box vs locknuts on an EMT connector. While not likely, it is possible the locknuts will work loose, but with two conduits into threaded entries those connections cannot come loose.
Note that it is my opinion that the code rule permitting conduits to support a box, requires that the box itself have threaded openings.

As someone who's had to rip out pool boxes I can 100% verify that 2 threaded rmcs won't just bust loose but all have seen a box hanging by a emt connector and 6 inches of wire to emt end.

3 or 4 emts I can imagine holding a box for practical reasons but it's not the same as a threaded for sure

 

[NoahsArc]

It's never been legal in my career, not sure when it was last legal.
1/4" threaded rod and a beam clamp or trapeze.

 

[kwired]

It's never been legal in my career, not sure when it was last legal.
1/4" threaded rod and a beam clamp or trapeze.

threaded rod doesn't necessarily give it a that much support, but does meet code.

About as brilliant of a requirement as needing a support on a 3 foot long piece of 4 inch rigid running between two cabinets.

 

[don_resqcapt19]

As someone who's had to rip out pool boxes I can 100% verify that 2 threaded rmcs won't just bust loose but all have seen a box hanging by a emt connector and 6 inches of wire to emt end.

3 or 4 emts I can imagine holding a box for practical reasons but it's not the same as a threaded for sure

As I said, it is a common practice in many areas to support boxes from EMT....I might have even done it a few times when I was doing commercial work a long time ago

 

[augie47]

Not having support was a very common rejection for folks who came into that jurisdiction from other areas. Seemingly not universally enforced.
Your picture was very reminiscent of those days.

 

[NoahsArc]

threaded rod doesn't necessarily give it a that much support, but does meet code.

I come from installing a ton of EMT/1900/11B runs over drop ceilings where the entirety is done off of rod, often a few feet in length. It is totally sufficient by itself (it does get swingy). I get that it seems a bit excessive for a box with strongly secured EMT going to it, but if that EMT is itself swinging from rods, you definitely want rod on the box as well, otherwise it's a big flex joint in the run: the locknut side of a connector has a lot less rigidity than the 1" of coupling-pipe.

You're looking here at just about the most secure form of EMT connections for a 1900, but in most circumstances I've installed it's a lot less secure than that (following code). Code isn't going to get bogged down in such details. While I agree in this case the EMT is sufficient, I won't argue the code either, and the bare minimum here is rod to fix that. AHJ's decision to care or not. Personally, I wouldn't, but if I'm installer, it's to code.

 

[cyoung6105]

Regarding the "new code" from the o.p. it is addressed in 314.23(E). "...It shall have threaded entries or identified hubs." From my interpretation, the set-screw type of connector does not qualify as a "hub or threaded entry."