310.15(B)(2)(c) (Ripped from another forum)

[cpal]

granted this appears to be an error in word selection. I agree that raceway would leave no doubt of the intent of CMP 6 when they adopted this language. but the issue (as we all know) was detrimental overheating of the conductors in raceways on rooftops exposed to direct sunlight.

The next question might be given the apparent error in selecting terms. Who amongst us (having knowege of 310.15(B)(2)(c) ) would ignore these requirments if installing tubing on a rooftop in direct sunlight??

 

[M. D.]

Is conduit defined in the NEC???

websters

c

on?duit
Pronunciation:
\ˈk?n-ˌd?-ət, -ˌdy?- also -dwət, -dət\

Function: noun

Etymology:

Middle English, from Anglo-French cunduit pipe, passage, conduct, in part from cunduit, past participle of cunduire to lead, from Latin conducere, in part from Medieval Latin conductus ? more at conduct

Date:
14th century


1: a natural or artificial channel through which something (as a fluid) is conveyed
2archaic : fountain
3: a pipe, tube, or tile for protecting electric wires or cables
4: a means of transmitting or distributing <a conduit for illicit payments> <a conduit of information>

 

[480sparky]

I agree. Mistake or not the words are the words. Says conduit, not tubing, so EMT isn't required to comply. If no one noticed soon after the 2008 became available this it make take two code cycles to correct it.

I don't see anything in the 2011 ROP that indicates anyone caught it.

 

[cpal]

Careful nit picking might re constitute article 315!!!!!!

 

[M. D.]

There is one for conduit body and it applies to tubing as well,.. I'm not sure that EMT is not also a conduit.

 

[Rockyd]

This would be a good time to get a formal interpetation

 

[iwire]

but the issue (as we all know) was detrimental overheating of the conductors in raceways on rooftops exposed to direct sunlight.

I agree that is the intent but it is not the intent that is enforceable.

The next question might be given the apparent error in selecting terms. Who amongst us (having knowege of 310.15(B)(2)(c) ) would ignore these requirments if installing tubing on a rooftop in direct sunlight??

Not many among us here at this forum would. I apply that section when sizing my PV system conductors that have already been over sized by 125% TWICE.

But plenty of sharp ECs might try to save some money especially considering that few of them will have actually seen roof top conductors damaged from the ambient temps.

Don't forget it was not a 'safety issue' until the moment the 2008 NEC was adopted. :smile:

Something more to consider.

Is a NEMA 4X Trough a conduit?

 

[iwire]

Is conduit defined in the NEC???

IMO it does not have to be, as I said compare the ".1s" of each raceway article.

 

[George Stolz]

Bob, you've been doing this longer than I have, and I know that an inspector (backed by his or her AHJ) can do just that.

Legally? Without an amendment?

I strongly disagree, if that was a fact we might as well use the NEC for TP.

I agree with your sentiment, but still believe the reality is different, at least in my area.

Looking at 90.4,

The authority having jurisdiction for enforcement of the Code has the responsibility for making interpretations of the rules, for deciding on the approval of equipment and materials, and for granting the special permission contemplated in a number of the rules.

Without any documentation, an AHJ can get more restrictive then the CMP intended, if the AHJ interprets the rules in a more restrictive manner.

Now, if the AHJ interprets the rule differently than your way, you have two interpretations. Your interpretation is that the rule doesn't apply to EMT, which I agree with. For argument's sake, let's say the AHJ's interpretation is that it does.

What is an interpretation?

? the action of explaining the meaning of something
? an explanation or way of explaining

Charlie's Rule does not apply to the result of an interpretation. It is a tool to reach an interpretation.

If an AHJ interprets the meaning of the word "conduit" as to mean "raceway" then where the rubber meets the road, in that jurisdiction tubing becomes conduit. If the disagreement continues, I suppose it would come down to who can afford the best lawyers.

 

[Flex]

i think the index is directly related to the code. If you also look under tubing it says see also conduits.

 

[Rockyd]

This would be a good time to get a formal interpetation

It doesn't matter what you think, it's a matter of what you know.

Don't forget - perception is everything

 

[ericsherman37]

I wouldn't want to put EMT on a roof anyway... the salt spray in the air around here would turn it into a rusty blob in no time at all.

But that being said... I say yes, the 310.15(B)(2)(c) adjustment factors would apply to EMT on a rooftop. Just because the CMP screwed up and specified "conduit and cables" instead of a more general term like "raceway," doesn't mean that the rooftop raceway will suddenly become a safe installation if it's installed in something other than "conduit." I don't think it would make it up the food chain very far if you appealed it - people are human, even, unbelievably, the Code Making Panel - and they can mess up. I bet they could find a method in the bureaucracy somewhere to make an "emergency code correction addendum" or some such were it necessary.

 

[ericsherman37]

I'm going to bring this to class with me - one of our instructors is the local electrical inspector, and I don't think he's mentioned this issue before.

 

[480sparky]

FWIW, I've found there's at least three proposals to the '11 to correct this:

 

[Flex]

All make sense. No reason not to change the wording.

 

[M. D.]

The folks that did the study of roof top conduits thought EMT was one

http://www.iaei.org/magazine/?p=1743

 

[Cow]

I'm going to bring this to class with me - one of our instructors is the local electrical inspector, and I don't think he's mentioned this issue before.

I'd be curious to hear what his response is?

 

[M. D.]

also remember the reasonable man test ...should the sheet hit the fan

There is in US jurisprudence a 'reasonable and prudent man' test which is used to determine if an individual should have forseen the consequences of an action.

 

[iwire]

I agree with your sentiment, but still believe the reality is different, at least in my area.

Looking at 90.4,

Without any documentation, an AHJ can get more restrictive then the CMP intended, if the AHJ interprets the rules in a more restrictive manner.

Now, if the AHJ interprets the rule differently than your way, you have two interpretations. Your interpretation is that the rule doesn't apply to EMT, which I agree with. For argument's sake, let's say the AHJ's interpretation is that it does.

So in your view the NEC is no more then TP for the outhouse?

There is a difference between an interpretation and making up a rule that does not exist and if an EC so desired they could take it to court and IMO prevail.

Had you said the AHJ does not have to accept EMT on a roof at all I might have to agree with that.

 

[iwire]

i think the index is directly related to the code. If you also look under tubing it says see also conduits.

The index is not the code, just like if you had a NEC handbook the commentary no matter who it is from is not the code.