ECN Forum Forums Code Related Discussion NEC & other Code issues Flexible Metal Conduit

Alan I also agree with George and raider1.

It is 300.22(C) that applies.

But wouldn't B still apply as it is still a "Duct", or "Plenum"? And, "specifically fabricated to transport environmental air"? It doesn't say distribution or return, just environmental. C says, "This section applies to space used for environmental air-handling purposes other than ducts and plenums as specified in 300.22(A) and (B)." I have always known this to be rooms and dropped cielings, even doors.

IMPO... 300.22 Does not say anything to the effect that it is "A", or "B", or "C" that apply soley to the space in question. But has added restriction on certain ones, and exceptions for others. Just because this "Duct" is made of sheetrock and lumber, and maybe a little sheetmetal too, it is still a duct!

I guess we can agree to disagree about whether the joist space in a dwelling is a duct or not but the facts of what wiring methods are permited and what equipment is permitted are rather clear when you read 300.22(C)(1) and (2). and then look at the comment in the Handbook. I know, I know but the opinion in the Handbook is close to being accurate. The commentary would have us not installing any boxes in the CA and only cables Listed for use in a plenum or in metallic wiring methods. Of course if we go perpendiclar to the air flow no metal wiring jacket is required.I'll have to change my ways and I can do that, I'm a big boy.

[This message has been edited by George Little (edited 11-07-2005).]

I don't think you want a device box in a return air "space" period. It will fill up with dust eventually because it is sucking air through it.

George,
The most important reason for inspectors to share information is to achieve consistant interpretation of the Code.
It is easy to get mixed up and most contractors would rather just do it the inpsectors way than disagree with the AHJ.
Few realize how much an inspector has to know just to be right most of the time.
Alan--Inspector

Alan- I would tell ypu that 90% of the electricians in South East Michigan have been installing boxes in CA returns for at least 30 years and then either boxing around them or using metal wiring methods. This BB has been a very good sounding board for promoting uniformity and that's why I stay tuned. The day we can't rethink something is a sad day for us as inspectors, contractors or engineers. Anyone that doesn't agree should un-bookmark this site. I'm not sure un-bookmark is a word but you get the drift

George, well said, and I agree.

I think un-bookmark should be a word.

Roger

Thanks George,
I have more respect for an electrician that questions one of my calls than one that just agrees.
I have been wrong.
Show it to me in the book.
"When I am wrong I change my mind, what do you do ?"
It doesn't feel good but, it forces us to be better.
Actually it makes me think about all those jobs where I was making the wrong call and I just hope that nobody got hurt as a result or that they weren't dumping on me when I was out of sight.
The AHJ is King. It is lonesome on top, but is is still on top.
Remember; If it was easy anybody could do it. And they wouldn't get the BIG bucks.

NOTE; Most inspectors are paid less than a third year apprentice. Yet they are supposed to know more than the Master electrician.
The Code stuff is easy for me it is dealing with what people do that makes me crazy.

I'm looking forward to retiring.

Alan--Inspector.