I've got a picnic shelter I'm giving a price on that will include lighting and a few receptacles. The wiring will not be exposed to the direct weather but will be exposed to humidity. Can regular romex be used or do I need to use UF cable ?? thanks..

Judgment call for sure. The '08 NEC has some new wording in 334.14(B)(4) that might apply since the code prohibits installation in damp locations. More than likely most most inspectors would buy it.

As a side note can anyone show me where the conductors in NM cable are identified as THHN?

334.14(B)(4)

I don't think NM-B has ever been allowed in damp locations.

I always believed it was because of the kraft paper packing that will wick up water.
The only question for the AHJ is how damp is that location?

Also since the outlets will be under the shelter on the inside of the post, will I need to use in use covers or just regular weatherproof outlet covers? Thanks.

They are not "THHN" they are just a 90c rated conductor of some kind, since that is all the listing commits to.

As a practical thing we might assume they are THHN, just because of manufacturing expediency but we can't prove it.
For that matter you might even assume they are THHN/THWN but you know what assume means.

Who would have thought the covers on NM conduit bodies and the straps for RNC were not made out of the same plastic as the raceway but I had a Carlon rep tell me they don't have to be (in the listing) and in fact, at the time they were not UV protected. I don't know if they ever fixed that.

I think snap covers would be appropriate.

from the southwire PDF for the romex product.

APPLICATIONS
Southwire's Romex SIMpull ® Type NM-B (nonmetallic-sheathed cable) may be used for both exposed and concealed work in normally dry locations at temperatures not to exceed 90°C (with ampacity limited to that for 60°C conductors) as specified in the National Electrical Code 1 . NM-B cable is primarily used in residential wiring as branch circuits for outlets, switches, andvother loads. NM-B cable may be run in air voids of masonry block or tile walls where such walls are not wet or damp locations. Voltage rating for NM-B cable is 600 volts.

I would say no to romex in that location because it would be considered damp. Also your are in a damp location for the cover as well not a wet location subject to pounding rain so a flip up wheater proof cover should be fine.

If it were me, I would spec Type UF, but with work being as tight as it is these days, maybe check with the local inspector so you don't price yourself out of the job if somebody else is bidding it in NM and knows for sure the inspector will allow it.
As they say... when in Rome...

... use Romex?

lol, Greg!

Actually, considering the use and potential abuse in this application, EMT or IMC would be the right way to do it, even if UF is allowed by the AHJ.

When I redid our community shelter I used EMT, bell boxes, rain tight connectors and snap covers. This was actually 8' up on the tie beam and under the roof.
This replaced UF in 1900 boxes, no covers, that was showing it's age. I also added GFCIs that they didn't have.

I'd pipe it. Do I get the job?

No, seriously, I'd put it in pipe. I never run romex exposed.

Guys,

I assume GFCI protection is installed.

Cable assembly:
The manufacturer "specs" the rating on the basis that the entire cable assembly (yellow sheath, conductors with 90 degree rating, and the paper wicking) is Intact.

Conductors:
There is no "rated as" marking on the conductors,
it is on the outside of the entire cable assembly.
(*) The "rated as" is marked
on the outside of the yellow sheath.
The individual conductors have no marking,
although I certainly agree it "looks" like THHN.
(*) The individual conductors
do not have a Nylon skuff resistant jacket (THHN),
thus the Thin poly-plastic Insulation is not protected
from the abrasion that normally occurs
during pulling the conductors through a conduit.
This implies that the conductors are not designed
to be pulled through conduit "naked".

Dry-Locations:
Technically, outside is outside, and the "pic-nic shelter" is really outside, and at least damp. Romex is not designed for 'damp' locations. At least put a Jbox up near the roof and run UF down the post.

In-Use Receptical Cover:
This appears to be a "Not Direct Rain" application,
so I would use flapper covers, as the minumum.

COMMENTS are welcome:

glene77is, Memphis, TN

Glene77is:

Welcome to ECN!!!

Good post for your number 1.

A safe assumption that GF protection is required.

The debate over the insulation on the insulated inner conductors is and probably will continue to rage on. There is a thread herein regarding the "N" (outer nylon) on THHN/THWN building wire, discussing the reasoning of the outer nylon jacket.

Without 'seeing' the picnic shelter, it's difficult to determine if it's damp or wet; many discussions have arisen on the geometry issues, regarding driving rain. The 'usual' settlement is to err on the side of caution, and install the WP in use covers.

BTW; you welcomed comments.....I welcome comments, and new topics.

Take care, stay safe.

I treated our shelter as "wet" in every regard but the "in use cover". I really avoid them unless absolutely necessary if they are not going to be "in use". They just become wasp condos.That is one of the places where I think NFPA has exceeded their mission.

If anyone would call me on it I would say we pressure clean this area once a month. 406.6(B)(1)Ex

Greg,


Is that the ONLY place where the NEC exceeded their mission? I am sure we can all find some other spots.

Man am I glad someone else wants to run pipe. Most of what I do is commercial, in places with lots of forklifts and other destructive things around.

Codes, and materials, really need to reflect the real world. I think a few parties have dropped the ball here.

First off, I object most strongly to the new NEC ban on NM in 'damp' locations. The ink was hardly dry on the 2008 NEC, and the home-inspector forums lit up with the 'discovery' that nearly every house is now wired 'wrong.' The reasoning? NM passes through the crawl space, which is a 'damp' location because of ground moisture and condensation.

That still leaves us with the issue of boxes and fittings. Even if someone were to run UF, the usual connectors are not suitable for anything but dry locations.

Greg mentioned the matter of insects nesting in boxes and covers. This is a very real issue, and is not addressed by any NEMA standard. Yet, anyone who has opened a fixture (usually while 20ft up on a shaky ladder) and disturbed a few thousand hornets will agree that these are "hazardous" locations!

There are likely millions of awnings, porches, gazebos, eaves, and other overhangs where NM has been in use for decades witout problem. You can wag your finger and say 'violation' all you want, but I have to question whether there's a hazard from NM getting "damp." Or, for that matter, even rained upon.

Since they went to the plastic jacket in the 70's, I can't imagine why the stuff is not rated for wet locations. I suspect all it would take is printing "NM-B" on the jacket, rather than just "NM." That is, I suspect the product would pass any test required of 'wet' location wire. The paper around the ground wire? Just try to make that wet - and so what if the ground wire gets wet anyway! Or, for that matter, just leave that wrap off alltogether, or use a mylar one (like they use in MC).

I think the code needs a reality check here.

I have heard a number of times that the "damp/wet" limitation on NM is because of the paper packing. I agree, it is the 21st century, why can't they use something that won't wick up water?
That would be NM-C I suppose.
My thought is, that would start nipping into the UF market and I bet UF is a higher profit margin product.
I wouldn't be shocked if someone said UF was actually cheaper to produce.
BTW has anyone seen NM-C? When I searched on the Southwire site a while ago it sent me to UF.

No... cause the trunk slammer who did it in Romex underbid you!