MC Tuff in Wet Location?

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busman

busman

Senior Member
Location
Northern Virginia
Occupation
Master Electrician / Electrical Engineer
The NEC says that MC cable can be in a wet location if the conductors are listed for use in wet locations. So - MC Tuff cable has THHN/THWN conductors, but the website says the following:

"Outdoors or in wet locations where the armor has an overall outer, moisture resistant PVC jacket and the conductors are wet rated"

The website also says:

"THHN/THWN (XHHW available by order subject to lead time and minimum quantities)"
I don't understand. Can I used MC Tuff (Galvanized steel armor and THWN conductors) in a wet location (no outer PVC jacket)?

Edited to add:

I also found this on the AFC website:

"In wet locations where any of the following conditions are met:
— The metallic covering is impervious to moisture
— A lead sheath or moisture-impervious jacket is provided
under the metal covering
— The insulated conductors under the metallic covering are
listed for use in wet locations and a corrosion-resistant
jacket is provided over the metallic sheath"

which looks similar to wha's in my 2005 NEC, but is DEFINTELY not the same.

Thanks,

Mark
 
Last edited:
Mark, in the 2008 NEC they have changed the rule, NEMA or the a manufacturer said it was a mistake in the first place.

IMO, between 110.3(B) for 2005 and the rule change for 2008 you can not run it in wet locations.

You can get 'Parking deck' MC which has the plastic overall jacket if you really want to use cable.
 
iwire said:
Mark, in the 2008 NEC they have changed the rule, NEMA or the a manufacturer said it was a mistake in the first place.

IMO, between 110.3(B) for 2005 and the rule change for 2008 you can not run it in wet locations.

You can get 'Parking deck' MC which has the plastic overall jacket if you really want to use cable.
Click to expand...
You have got to see that stuff rip apart when the concrete settles. Shorts all over the place so now what do we do. Now that it is all exposed we had to rewire in gal. OUCH.$$
 
quogueelectric said:
You have got to see that stuff rip apart when the concrete settles. Shorts all over the place so now what do we do. Now that it is all exposed we had to rewire in gal. OUCH.$$
Click to expand...

You think conduit would have stopped the settling? :-?
 
dcspector said:
Impervious is the key word regarding the jacket/clad: Incapable of being penetrated.
Click to expand...

Under the 2005 you do not need a jacket that is Impervious, all you need is conductors that are type W.

In other words standard run of the mill MC could be used in wet location, FMC as well.
 
Thanks. I was starting to think I was losing it. So what I found on the AFC website matches the language in the 2008 NEC. I guess I'll have to break down and buy 2008, even though we are only up to 2002 in Virginia.

Mark
 
iwire said:
You think conduit would have stopped the settling? :-?
Click to expand...
I think they undermined the next garage a little too far all of the stairwells started to pull away from the structure about an inch or so cracking all of the block walls. They found huge shoring equipment very quickly before they lost the whole garage.
rigid pvc has a little wiggle room to it and pressure creates heat which will help the stretch/bend process without shattering . The next parking garage next door we used pvc in the fillagree pour with much better results. Only lost a few pipes
 
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