Burrito Q: Fastening of EMT

[Jim W in Tampa]

"Q 3. When EMT is installed within metal studs and it is not resting on the bottom of the opening, is additional support required?

A 3. Horizontal runs of EMT is considered supported by openings through framing members where securely fastened within 3 ft of termination points [358.30(B)]. The key word here is "supported". If the raceway is not resting on the framing member, then it is not supported. This does not mean that the conduit must rest on every framing member. As long as it is resting on one framing member every 10' and it is securely fastened within 3' of the tubing termination points, the installation complies with the NEC. "

Has nothing to do with the situation of truss webs.
In a wall the emt can not move very far. Laying on a truss it could move far enough to become uncoupled at a coupling. They need support and secured.

But i am all for getting Mikes input on this post.

 

[jusme123]

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[acrwc10]

I did not see the 'how would acrwc10 like to see it done' option on the pole.

Nope. :grin:

Consider this from the 2005 ROP.

IMO that clearly shows the CMP is aware that conduits laying on trusses do not have to be fastened every 10' and they see no real issue with it.


This is what the CMP says in 8-17

Happy Now :grin: I voted "NO" just in case you couldn't figure out where I stand on the issue. How long will this burrito have been laying around before the winner is decided?

The 2005 CMP response is, IMO, responding to the fact 110.12 was used as substantiation. If he had based his argument on any other reason the panel may have made their decision differently. If you want to get dismissed quickly in an argument just quote 110.12

Like I said in an earlier post, it would not pass inspection here.

 

[iwire]

Has nothing to do with the situation of truss webs.
In a wall the emt can not move very far. Laying on a truss it could move far enough to become uncoupled at a coupling. They need support and secured.

But i am all for getting Mikes input on this post.

Sorry Jim that has everything to do with it, if you can not see that then you have not been following the thread.:roll:

The EMTs are not required to be fastened each 10' when installed in framing members.

 

[iwire]

How long will this burrito have been laying around before the winner is decided?

Will it make difference, it will taste the same today as it will in a year.

Like I said in an earlier post, it would not pass inspection here.

So either they have a local amendment or you are assuming or they just do not know the NEC.

 

[charlie b]

The EMTs are not required to be fastened each 10' when installed in framing members.

Paragraph "A" says they do, paragraph "B" has nothing to contradict that, and the words before paragraph "A" tell us to do "A" and "B."

Keep in mind that "A" and "B" talk about different things. They are not different approaches to the same task. One speaks of securely fastening something. The other does not say it's OK (under certain conditions) not to securely fasten that something.

I just can't make it work out your way, Bob.

 

[steve66]

I agree with you. Looking more closely at the wording.

• Securely fastened in place AND supported . . . .
• . . . in accordance with 358.30(A) AND (B).

I still believe this was intended to be permitted. If 358.30(B) wasn't meant to provide some relief from the requirements in (A), then (B) is a complete waste of ink.

Steve

 

[iwire]

I just can't make it work out your way, Bob.

That is fine if you wish to remain incorrect about this code section.

I will side with Mike, Smart$, the CMP, myself and commonsense. :grin:

 

[iwire]

I still believe this was intended to be permitted. If 358.30(B) wasn't meant to provide some relief from the requirements in (A), then (B) is a complete waste of ink.

Exactly.

To read it Charlies way B serves no purpose whatsoever .... none ..... bubcuss.

 

[charlie b]

If 358.30(B) wasn't meant to provide some relief from the requirements in (A), then (B) is a complete waste of ink.

If that is the intent, then it is not a waste of ink, but rather an omission of some necessary additional ink. If they were to have added the word "only," and placed it between "fastened" and "within," such that paragraph "B" would have read, ". . . and securely fastened only with 900 mm (3 ft) of termination points. . . ," then it would have clearly conveyed that intent. But the word "only" does not appear in paragraph "B."

 

[charlie b]

I will side with Mike, Smart$, the CMP, myself and commonsense. :grin:

I will side with "Charlie's Rule," and assert that the words, as written, do not support your point of view. If you wish common sense to prevail, then submit a proposal for 2014, and get the words changed so that they say what you (incorrectly) think they say now.

 

[Jim W in Tampa]

358.30 securing AND supporting. EMT shall be installed as a complete system in accordance with 358.30 (a) AND (b) or permitted to be UNSUPPORTED in accordane with 358.30 (c)

It say AND so we must comply with both A and B
We cannot use C as this is over 18 inches.
It is is plain english with no gray mud.
Your trying to missuse use B to mean trusses and that simply is not what it says.

If your going to use that idea then we can run romex through wood trusses as they are framing members with VERY LARGE openings.

Now where is my burito ?

 

[mxslick]

It say AND so we must comply with both A and B
We cannot use C as this is over 18 inches.
It is is plain english with no gray mud.
Your trying to missuse use B to mean trusses and that simply is not what it says.

If your going to use that idea then we can run romex through wood trusses as they are framing members with VERY LARGE openings.

Exactly. Now I'd like to see someone try to do a romex install IAW the opinions of those who think this EMT install is legal and see what happens. :roll:

 

[iwire]

Exactly. Now I'd like to see someone try to do a romex install IAW the opinions of those who think this EMT install is legal and see what happens. :roll:

So both the CMP and Mike Holt are just plain wrong?

Interesting.

 

[iwire]

If your going to use that idea then we can run romex through wood trusses as they are framing members with VERY LARGE openings.

Jim the rules for NM are different, they specify 'holes or notches' not just 'through'.

And if you read the ROP I posted for EMT you can see they are talking about the large openings in trusses.

You get no Burrito

 

[billsnuff]

IMHO (which ain't much) 358.30 is about Securing and Supporting. Two subjects, not one, but both acceptable. I think A & B are the menu.

Otherwise there is no reason to repeat the 3 ft. requirement in both A and B.

If you are securing do A and if you are supporting do B.

 

[mxslick]

So both the CMP and Mike Holt are just plain wrong?

Interesting.

As much as I respect Mike Holt, yes. Both he and the CMP have the interpretation of this issue wrong.

Bob, no one is perfect, not you, not me, not the CMP and not Mr. Holt. We all make mistakes and in this case "they" are all wrong.

Unfastened conduit in open trusses is most certainly subject to movement beyond what the couplings would safely withstand, from accidental contact, hanging loads, deliberate contact and possibly even seismic movement. Heck, in a long run even the forces of pulling in the conductors could cause couplings to separate if the conduit is not securely fastened.

Here's an experiment for you all who have access to a truss system to do a test:

Connect two runs of 1/2" or 3/4" EMT, with a single 90 at each end.

Simply lay one in the truss webs and secure the other at no more than 10' intervals as required by Code.

Pick any size and numbers of conductors to equal 75% fill.

Pull those conductors into each run and see what happens.

At the absolute minimum, I promise that the unsecured run will be moving around and making the pull harder, IF none of the couplings don't pull apart.

The 10' rule is there for a reason people. :grin:

 

[charlie b]

So both the CMP and Mike Holt are just plain wrong?

Regarding the CMP, if you are alluding to your post #48, nothing in that ROP gives us the CMP's opinion on this question. They rejected a proposal because it lacked technical substantiation. But they did not say whether the proposed idea had some merit, or no merit, and their response did not say anything at all about the need (or lack of need) to fasten EMT at 10 foot intervals.

Regarding Mike's published comment on this question, I disagree with his opinion. He would not object to people disagreeing with him, especially if they provide a technical basis for their own opinions. He is certainly welcome to disagree right back at me, as you are doing, and I respect all opinions.

 

[steve66]

Attached is one from the 2005 handbook (kudos to those who pointed that out.)

The exact same wording is used for both the IMC paragraph 342.30(B)(4), and the EMT paragraph 358.30(B), but I don't see anyone claiming the illustration is wrong.

Your trying to missuse use B to mean trusses and that simply is not what it says.

It seems to me that "framing members" has to mean the same thing both in 358 and 342.

 

[Jim W in Tampa]

Jim the rules for NM are different, they specify 'holes or notches' not just 'through'.

And if you read the ROP I posted for EMT you can see they are talking about the large openings in trusses.

You get no Burrito

I did read it and it said nothing about trusses. What your suggesting is just lay runs of EMT on top of the tusses and ignore A. That must be a real first class looking job to pull wire through.
As far as what Mike was talking about he is talking walls not trusses. Am sure you have his phone number. Save us all time and have him cast his vote.