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MC in wet locations #96761 12/24/05 01:58 PM
Joined: Jul 2004
Posts: 9,482
G
gfretwell Offline OP
Member
Most MC I see is listed "wet location" but do they make a wet location connector?
How do you keep the water out of the box?


Greg Fretwell
2017 / 2014 NEC & Related Books and Study Guides
Re: MC in wet locations #96762 12/24/05 02:40 PM
Joined: Jan 2004
Posts: 1,507
G
George Little Offline
Member
Can't keep it out. Best advice I'd give would be to provide a drain hole. Something like we have for signs. See 600.9(D) for size for signs. Probably wouldn't need to be that large diameter for boxes but the concept is the same. If one installs the MC cable with a drip loop this would help. Also look at 225.22 and Exception. Interesting.


George Little
Re: MC in wet locations #96763 12/24/05 03:01 PM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
The only MC I have installed in wet locations is what we call 'parking deck cable' which is jacketed MC. There area WP connectors for it.

As for standard MC I think George is onto it.

Quote
348.12 Uses Not Permitted.
FMC shall not be used in the following:
(1) In wet locations unless the conductors are approved for the specific conditions and the installation is such that liquid is not likely to enter raceways or enclosures to which the conduit is connected


It goes without saying MC is not FMC but I think we could apply the same logic.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: MC in wet locations #96764 12/25/05 02:48 AM
Joined: Jul 2004
Posts: 9,482
G
gfretwell Offline OP
Member
There just seems to be a disconnect between the people who insist that EMT connectors are raintight and the guy who thinks MC or FMC is OK.


Greg Fretwell
Re: MC in wet locations #96765 12/25/05 01:01 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
Member
I was also surprised to learn that MC is approved for wet locations; all the connectors I've seen are marked "dry only."
I also note that a similar product- AC - is NOT approved for wet locations.

I am guessing that the insulated full-size groound, and the plastic (rather than paper) wrap of the wires are the reasons for this approval.

I am also guessing that the intent is to allow MC to pass through a wet location, without requiring a change in wiring methods.

Re: MC in wet locations #96766 12/26/05 12:03 PM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
Quote
There just seems to be a disconnect between the people who insist that EMT connectors are rain tight and the guy who thinks MC or FMC is OK.

Good point. [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: MC in wet locations #96767 01/01/06 04:02 PM
Joined: Mar 2001
Posts: 345
T
tdhorne Offline
Member
Quote
There just seems to be a disconnect between the people who insist that EMT connectors are rain tight and the guy who thinks MC or FMC is OK.
Did you mean to say
Quote
There just seems to be a disconnect between the people who insist that EMT connectors should be listed as rain tight and the guy who thinks MC or FMC is OK.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison


Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison
Re: MC in wet locations #96768 01/02/06 12:11 AM
Joined: Oct 2004
Posts: 135
B
BobH Offline
Member
I've seen it strung from a house to a garage and I thought for sure this was a violation when I first saw it, then I checked its listing, I was wrong. It's raintight and I can see a few scenarios where this would be very convenient.

Re: MC in wet locations #96769 01/02/06 02:17 PM
Joined: May 2002
Posts: 132
E
elektrikguy Offline
Member
Interesting timing on this thread....I just finished wiring an exhaust fan for a dishwasher in a commercial kitchen. It was the type with the 1/2 inch tube for the wire to drop through and was roof mounted. The duct guy promptly told me that I needed to install sealtite and a pitch box. He said he has never seen MC used in his career I peeled back the aluminum armor and exposed the THHN-THWN conductors to him.

Re: MC in wet locations #96770 01/02/06 03:06 PM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
We always use MC for that application. [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts

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