Conduit VS sleeve

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wet locations

wet locations

benaround said:
220/221,

Here's the deal, In arizona there are only two wet locations, one is inside

a carwash and the other is the bottom section of a boat. Add to that the

.4101" of yearly rainfall and even that vaporizes in about 1/2 hr.

On the other hand Az. has locations not listed in the NEC, some are, dry

locations, some are so very, very, dry locations, and some are so dry so hot

you can't touch it locations, of these, NM still should not be sleeved outdoors!
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The desert southeast has no wet locations!
 
Ok. For all the smug clowns claiming superior knowledge, it's OK. I'm a big guy and I can take it but I would honestly like to you to dig deep within that cache of information and tell me a couple of simple things.

1) What is a "multi wire conductor" as referred to in 225.10 in the 2005 NEC?

2) How would you install the circuit to a residential rooftop AC?

That's all I want to know. If you don't know the answer it seems that you would just not respond or say "I don't know" If you want to dodge the answer and carry on about what a hack I am and how terrible the inspectors are here fine. Knock yourselves out.


Or you could just listen to everyone in this thread any go buy some UF cable.
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Dude, you are not understanding my question. I'm not asking how to do it legally. Use 8/2 UF for the AC circuit...I GET it, OK?

What I am asking is
1) why is it allowed in literally milions of applications and
2) How do YOU do it?



To answer your question I run out of the disco with a sealtight whip and thhn/thhw into the unit.
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You guys are just messing with me...I just know it. HOW does this answer my question? You left out the important part...the ONLY part I was asking about. How do you get INTO THE DISCO??? I KNOW I have difficulty sometimes expressing my thoughts but I don't know how else I can phrase this.

One more time.You have you NM running thru the attic and at some point it has to exit thru the roof and go to the AC unit. How do you get it there?

Ours are almost always on concrete pad.What is reason behind on the roof ?
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Rooftop units are less expensive to install. It's a package unit with the condenser and evaporator in the same unit. It is by far the most prevalant system in the southwest.
 
300.9 in 2008 NEC removes all doubt about the inside of a raceway in a wet location. It has been almost everyone's opinion that conductors and cables installed in a raceway outdoors had to be of a type listed for wet locations. The fact is, the NEC never really said that. The only 2 places where it came close to saying that were 300.5 and 314.30(C), and these sections deal with underground installations.

358.42 says that EMT fittings installed in wet locations shall comply with 314.15(A) which says they shall "...prevent moisture from entering...".

312.2(A) says that if a conduit enters an enclosure above uninsulated live parts that the fittings have to be listed for use in wet locations. If the inside of the conduit is a wet location, isn't the inside of the enclosure and the uninsulated live parts in a wet location also???

So.... It's probably a reasonable argument that the inside of this conduit meets the Art. 100 definition of a dry location. (Until the 2008 code gets adopted)

220/221 said:
No need to be snippy. I am just looking for opinions and answers. You can move on if you like.

I am the kind of guy that like to know "why".
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Looking for opinions and answers and wanting to know "why" are good qualities. Don't lose that. :smile:
 
220/221 said:
One more time.You have you NM running thru the attic and at some point it has to exit thru the roof and go to the AC unit. How do you get it there?
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No rooftop AC where I am, but I do have a similar setup for a chimney fan.

1) NM connects to THHN in attic J-box
2) THHN runs through FNMC penetrating the roof
3) FNMC and power whip connect to J-box mounted to chimney
 
2) How would you install the circuit to a residential rooftop AC?
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If I had to wire one I would use a conductor listed for use in a wet location. Maybe you will have to use MC cable for the unit, maybe UF cable, maybe run THWN in flex.

But you can not use NM outdoors even in a raceway.

The fact that it has been allowed in your area does not make it right.

In the 1980s I would use NM in the LFMC whip from the disconnect to the unit on ground mounted HVAC units.

We don't anymore, codes change, inspectors get sharper and we electricians learn what we have been doing has been or is now a violation.
 
JohnJ0906 said:
The commentary to 348.12 doesn't say anything close to this, and I didn't see it in other articles either.

I'm not trying to bust anyones chops, or anything, but I would like to know where this QUOTE came from. :smile:
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I am the one who posted that commentary. It comes from Article 100 definition of, "location, wet" in the 2005 NECHB.

Chris
 
http://www.afcweb.com/pdfs/afc_pdeck_flyer.pdf

This cable would be a good choice, and as I understand it ,..it will require no further adjustment for roof top applications

2008 NEC


Quote:

310.15(B)(2)(c)
Conduits Exposed to sunlight on rooftops. Where conductors or cables are installed in conduits exposed to direct sunlight on or above rooftops, the adjustments shown in table 310.15(B)(2)(C) shall be added to the outdoor temperature to determine the applicable ambient temperature for application of the correction factors in table 310.16 and 310.18
 
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raider1 said:
I am the one who posted that commentary. It comes from Article 100 definition of, "location, wet" in the 2005 NECHB.

Chris
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Chris, thank you!

I have been having a "spirited discussion" about this with a co-worker, and he challanged me to find something in writing. NECHB commentary may not be enforcable, but it will get me a cup of coffee! :D
 
Is a sleeve a raceway? I would say no.

Until recently you could not put NM in a conduit anyway, so it would be a violation just for that reason.

I vote for a jbox in the attic and some kind of conduit with THWN wires out the roof to the A/C unit.
 
JohnJ0906 said:
Chris, thank you!

I have been having a "spirited discussion" about this with a co-worker, and he challanged me to find something in writing. NECHB commentary may not be enforcable, but it will get me a cup of coffee! :D
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You are very welcome, enjoy your coffee.:)

Chris
 
I vote for a jbox in the attic and some kind of conduit with THWN wires out the roof to the A/C unit.
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That seems like a legal option but not a very good one. Here the attics that ARE are accessible are really only "technically" accessible.....ie: if you weigh under 150 and dont mind crawling thru 3 foot of blown in insulation in the 150 degree heat. It also seems like one extra splice which equals one extra place for trouble.

I think I should write the next code.
 
electricmanscott said:
Why does this make me nervous? :D
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Dude, I'd be good at it.:rolleyes:


I'd not only ALLOW NM to be protected in emt I would require ANY cable to be protected unless it was in the wall/attic. It cracks me up that cable can be strung outside a house but protecting NM with emt is considered unsafe. You can try ro defend it by saying "it's the law" but that don't make it right.

I would also ban underground IMC. In my illustrious career I have seen COUNTLESS failures of undergound RMC/IMC and ZERO failures of NM in conduit.

I would also ban the phrase "refer to section...." in the book and translate it to English.
 
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