ECN Forum Forums General Topics of the Trade General Discussion Area anybody use romex going to ACs?

Seeing as RMC couplings are running thread, wrench tite makes little difference in whether or not rigid conduit is liquid tite. I'd say its not depending on where it is.

I would consider the inside of a raceway to be a wet location if the environment the race way in placed in is a wet loaction. I was always told that threads made up wrench tight are for grounding and physically vialble reasons, not to keep water out. Which is also why we don't dope our threads. If we were trying to keep it water tight, shouldn't we use pipe dope?

Just last week I was changing wires out in a residential remodel. This was a 2nd floor bedroom originally done in EMT. Who would dare call this a wet or damp location? Yet my hands were covered in rust at the end of the pulls. And if this is the case in a dry location, how much more could we expect this in a wet loaction??

A short aside off of the topic.

Bridgeport now offers raintight EMT fittings. www.bptfittings.com/catalog/250-RT2.shtml
...S

[This message has been edited by electure (edited 02-23-2004).]

An unprotected location exposed to the weather is by Article 100 defined as a wet location. 300.7 requires conduit sealing in dry locations where subject to temperature changes. 310.8 (C) requires all conductors installed in wet locations to be of a type listed for use in wet locations (or W in the insulation designation), or have a moisture-impervious metal-sheath (MI cable).

I don't see NM cable meeting these requirements. The letter of the code would require any conductor installed outdoors to be water proof (W). The AHJ could NOT, by building code, allow site specific circumstances and his considerable experience to "bend" the rules. He would be sticking his neck out, although it is done every day.

Section 109 of the IBC: "Inspections presuming to give authority to violate or cancel the provisions of this code or of other ordinances of the jurisdiction shall not be valid." The IBC references the NEC through the IEC.

So, you would take your chances if you don't use the proper wire type for the circumstances. You wouldn't use 30 volt wire for line voltages would you? It works for a while, then SNAP, CRACKLE, POP. Or, how about using #12 for a 30 amp load? It probably won't ever fail, but if it does, YOU will be liable!

Earl

I have to agree with Earlydeans comments.

"Liquidtite" does not define as "waterproof" does it??

As 'raintite" does not define as 'waterproof' either.

Playing wordsmith with terms that can be defined by each persons opinions, is akin to thinking that everyone in the world has the same definitions for all words and phrases.

IMHO, if it's outside, it's 'wet location', if it's inside/outside and subject to temp variations, it's "wet".

What's the big deal?? THHN/THWN is rated for both locations, the cost is not prohibitive, and it's a widely stocked/available item.

INHO, stripping NMC as described within the previous comments is a 'short-cut', and 'saves' having to handle another type of conductor, and having it on the job.

Is this practice commonplace, YES, is it "CODE"; NO....does it fail....YES, if the AHJ opens the disco to check! Can the stripped NMC conductors deteriorate, probably YES, over a period of time.

Ryan J.....what do you say???

John

Taking NM cable, stripping off a length of the outer sheath, inserting it into a junction box, and then going out of that junction box though a length of FNMC as a whip doesn't strike me as a way to do less work or save money; it takes time and effort to strip that cable and then fish it.

I see as benefits: not having to go out and find the small length of THHN/THWN, and not having to make a splice in the junction box.

The downside is that the conductors inside of NM-B are THHN conductors, and are not individually printed as being THHN conductors; they are part of a cable assembly. Given the materials that they are made of, the conductors would _probably_ be able to pass the tests to be THWN conductors, but they have not been tested.

Question: in this same situation would it be _better_ to simply use UF-B cable, both for the interior wiring (where it is permitted to be used as NM-B cable) as well as inside the FNMC whip? UF-B is rated for wet locations and for direct burial. I presume that the whip would need to be large enough to properly hold the UF-B cable assembly.

Further question: What about using the UF-B with the sheath stripped off in the FNMC whip, as in the original post? In this latter case, if the individual conductors are not labeled THWN, but a data sheet for the cable lists that the conductors are THWN, would having this datasheet make a difference in terms of allowing this installation?

-Jon

are we the only ones who simply use a piece of 8/3 seu from the disconnect to the unit?

[info] I'd normally terminate in a 1900 and would feed THHN/THWN through the LFNMC/LFMC - Besides, 99% of my work is done in conduit, and we use 100% THHN/THWN anyway.

I've just been doing a fair about of NM/NMB lately, and I'm interested about the interpretive part (AHJ) of this discussion. [/info]

Hotline



What?

Liquidtight is not waterproof?



Reading the above makes it sound to me that the NEC considers LFMC as protection from liquids, if a conductor is protected from a liquid why would it have to be rated for wet locations?

Your right, it is not a big deal to use THWN or RHW, I have and will continue to do so.

I am just in this for the interpretation.

Bob

Bob,
Wouldn't you have to seal the ends for it to be waterproof?

Is there anything that says that the wire in NM cable is THHN or THWN, or anything else for that matter?
We might see it as such, but actually it's only 90°C wire, a part of the cable, listed as NM.
I just "stripped out" a piece here, and the conductors aren't marked
Unless they're marked we have no way of knowing, and also technically we can't use it per 310.11(A) and (B)
...S