Use the box for support of the conduit?

[George Stolz]

Here's a question I was asked to ask the membership here, I did not have an answer.

Click on image for more details on the product.​

We use Caddy products quite a bit. We use these hangers to support the conduits entering the box.

We always use the allthread that is suspending the 4-square box in the air to support the hanger, which is supporting the conduit.

Is there a code stating that I cannot attach another of these hangers directly to the box with a 1/4-20 bolt and nut? It would be relying on the box instead of a direct connection to the all thread to support the conduit.

 

[JohnJ0906]

What do the instructions say?

It looks like the picture (bottom left) shows just what you are describing.

 

[bjp_ne_elec]

From the pic, it also looks like there is a series of holes on what would be the back side of the box. Why not just run a 1/4"-20 x 3/4" with 1/4" nut on the back side?

Actually just check Caddy's web site, and these are B18 series, and they specifically call them "combination box and conduit supports.

Sorry - I mis-read the OP. You would have to connect to the 1/4" threaded rod with the additional box - as the 1/4" rod is the "support". For some reason, when I originally read it, I thought you were wondering if you had to also support the box - as one could get the impression from the pic, that just the conduit is being supported.

 

[infinity]

Is there a code stating that I cannot attach another of these hangers directly to the box with a 1/4-20 bolt and nut? It would be relying on the box instead of a direct connection to the all thread to support the conduit.

Is there a code section that says you cannot do this? I would ask does it really matter? The intent of supporting both the box and raceway has been satisfied therefore the installation is code compliant.

 

[Pierre C Belarge]

Is there a code section that says you cannot do this? I would ask does it really matter? The intent of supporting both the box and raceway has been satisfied therefore the installation is code compliant.

Take a look at 314.23(E) Raceway Supported Enclosure, Without Devices, Luminaires (Fixtures), or Lampholders.


While your at it, take a look at the next section as well. Just for future reference.

P.S. How much of Caddy/Erico stuff is actually listed? ...just a question for thought.

 

[Dennis Alwon]

I understood that George had supported the box and wants to support another box from that box. Is this not what he was asking???

 

[infinity]

I understood that George had supported the box and wants to support another box from that box. Is this not what he was asking???

I'm guessing but I think that he wants to support the box and then support the conduit with one of the Caddy products he posted. IMO once they're all bolted together they become one giant collection of supported pieces.

 

[George Stolz]

• A beam clamp is secured to a beam.
• A 1/4-20 all-thread is screwed into that clamp and secured.
• A 1/4-20 nut is threaded onto the bottom of that all-thread,
• A hanger is slid on up to the nut,
• A four-square box is slid on up to the nut,
• Another nut is installed and tightened inside the box, to hold the box and hanger in place.

Now, this all-thread will support the box, and two 1/2" conduits entering the box on opposite sides of the box.

Now, the installer wishes to put another conduit into the box, on a knockout beside the center one just used. He:

• Rests the hanger on top of the box for a moment,
• Grabs a 1/4-20 x 1/2" screw and a nut,
• ...and connects the hangar directly to the box, through one of the existing holes in the back of the four-square beside the all-thread.

Legal or not?

Edit to add: The problem is, are the additional raceways considered supported, by connection to the four-square box? The box is already supported and fine. The two raceways in the center of the box, with the hangar through the all-thread, are fine.

Are the two raceways next to the center raceways also fine?

 

[Smart $]

I understood that George had supported the box and wants to support another box from that box. Is this not what he was asking???

I believe that IS what he is asking.

The answer to his question as stated is: No, there is not any NEC code "stating [one] cannot". Yet, there is no code stating you can. Section 314.23 lists methods which one can use to support boxes, and supporting a box from another box is not among those methods.

EDIT: Just read George's latest post and that apparently IS NOT what he is asking

 

[George Stolz]

Here's a picture that might help:

View attachment 448

The blue hole in the box has an allthread through it, and is supporting the center pipes (by means of the hanger), and the box. This is what is shown in the pictures from Caddy above.

The red hole has a hangar that relies on the box to support the raceways.

Is the red hole legal?

Edit to add: Smart posted while I was typing, let me clarify: There is only one box in question. It is the support of the raceways that I am trying to address.

 

[Smart $]

The red hole has a hangar that relies on the box to support the raceways.

Is the red hole legal?

IMO, no. I can't cite a code because there is none covering such. It comes down to permissable methods of supporting conduit are covered and using a box as a means of support for conduit is not one of them.

Drop another allthread to support the "hole" and you're good to go.

 

[S'mise]

I wouldnt think so either. It comes down to common sense and the AHJ. If its only one box securing a section of 1/2"EMT that's one thing. If you have 200 feet of boxes like this and using them to support 2"RMC to whole lenth thats quite another. As far as code, is it following the instruction of the manufacture? Those clamps are rated for only so much weight.

 

[peter]

ERICO = Electric Railway Improvement COmpany

On page 68 you have the relevant information. The figure 5 seems to be designed for multiple runs.
Arlington and Erico [Caddy] are two leading manufactrers who are actually trying to make us electricians' lives easier. The clamp in question, 812MB18A, is actually a rather flimsy method of suoort -- if you're concerned about such things. But it satisfies the Code.
That figure 5 thing seems to be a flat plate that you can mount additional hangers from. If you can do that, then I don't see why you can't run another hanger from the box itself.
`Peter

 

[Smart $]

That figure 5 thing seems to be a flat plate that you can mount additional hangers from. If you can do that, then I don't see why you can't run another hanger from the box itself.

You can do that because the combination hangar is supported by the threaded rod, wire, or structural element (as in the following image)... not the box.

 

[George Stolz]

Thanks for all the replies, I think everybody can see what I'm asking, and where the confusion is coming into play here.

This actually came to a head at work because several of the temps we had work in our hour of need were not using the all-thread, they were using anything to get the bracket secured. Tek screw into the bracket, 1/4-20 through the box - all of them were as secure, but we were under the impression it was illegal to use the box.

A couple of us started wondering why/where it was illegal.

So we have pros:

IMO once they're all bolted together they become one giant collection of supported pieces.

That was the guy's argument who put me up to this.

The clamp in question, 812MB18A, is actually a rather flimsy method of support -- if you're concerned about such things. But it satisfies the Code.
That figure 5 thing seems to be a flat plate that you can mount additional hangers from. If you can do that, then I don't see why you can't run another hanger from the box itself.

The flimsy aspect of this does weigh heavily on the discussion, IMO. (Sorry for the pun. ) If this flimsy bracket can hang on an allthread, it is the weak link.

If it hangs on a box, it is still the weakest link, and no weaker than if it is screwed with all-thread, IMO.

And we have cons:

IMO, no. I can't cite a code because there is none covering such. It comes down to permissable methods of supporting conduit are covered and using a box as a means of support for conduit is not one of them.

358.30(A) is satisfied with the blue hole used; why not the red one? There is no list of acceptable means of support, so I don't know how we'd come to an answer down that path.

There are clear sections that forbid raceways from holding each other up. Isn't it a glaring omission if there is supposed to be a rule forbidding a box from supporting raceways?

And undecideds:

What do the instructions say?

As far as code, is it following the instruction of the manufacture?

To be honest, I feel rather stupid for saying so, but I don't recall seeing (maybe because I didn't look for) instructions.

There might have been none, because it is a fairly self-explanatory device.

The Caddy catalog I have (and the link from the OP) are silent on it - they don't even mention the load rating. The most likely reason I can think of for this is that there is a max-size conduit that fits them (3/4") and they know how much a fully laden conduit weighs, and therefore they don't care as much as they do about the clamps that are designed to support a full ten feet of conduit.

 

[benaround]

George,

358.30(A)exp.#1 , permits the BOX as support in this exception,FWIW

2005 NECH exhibt 358.2.

 

[benaround]

George,

Another thought would be to put both Caddy brackets thru the allthread

but put one on a slight angle and turn the clamping part of the bracket so

the pipe will go thru it straight.

 

[Smart $]

And we have cons:

358.30(A) is satisfied with the blue hole used; why not the red one? There is no list of acceptable means of support, so I don't know how we'd come to an answer down that path.

Well it isn't the "blue hole" that supports the combination hangar... it's the threaded rod and nuts that support it while incidentally supporting the box. Remove and replace the rod and the upper nut with a 1/4?20 bolt and your raceway system remains [better] secured but not securely fastened in place?which requires attachment to something other than the raceway system itself?and neither box nor conduit is supported?the latter of which requires attachment to something other than the raceway system itself, too. This is exactly what is proposed for the "red hole".

There are clear sections that forbid raceways from holding each other up. Isn't it a glaring omission if there is supposed to be a rule forbidding a box from supporting raceways?

I suppose it would be a glaring omission if there weren't a couple sections that spell out how conduits can support boxes and the like. Yes it is a stretch, but not all that long of one, to say if conduits support a box, then the converse cannot occur. The NEC doesn't cover all potential scenarios of an installation, much to the chagrin of many :wink:

 

[George Stolz]

The NEC doesn't cover all potential scenarios of an installation, much to the chagrin of many

To which I would reply, the NEC is a permissive document. If it does not prohibit an installation, then the installation is compliant.

Here are the installation instructions, I found some in a box today.

I'm sitting on the fence at the moment, I'd be interested in more replies, if someone hasn't spoken up yet. (And of course, those who have replied, thanks and continue... )

Edit to correct some things, and add:

If I use a regular 1/4-20 nut and not the Caddy brand nut, am I violating the listing?

View attachment 459

 

[Smart $]

To which I would reply, the NEC is a permissive document. If it does not prohibit an installation, then the installation is compliant.

Touch?... but its not about permitted versus prohibited. Simply a matter of meeting the requirements. The gray area is introduced by lack of technical defintions and criteria.

Here are the installation instructions, I found some in a box today.

Online pdf version.

If I use a regular 1/4-20 nut and not the Caddy brand nut, am I violating the listing?

That would be my guess :roll: