At one time, was MC and/or AC cable rated for wet locations?

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zappy

Senior Member
Location
CA.
Old building with MC cable running on roof feeding lights. Probably 20+ years old. Thank you for your help.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I've even seen one of them direct-buried, but don't know which it was, nor the rules back then.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Don't believe I've ever seen AC with it but they do make MC with an outer plastic covering that is listed for wet locations and direct burial but it is only available in larger conductor sizes.

Normal AC and MC is dry locations only. Always has.

-Hal
 

augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
Don't believe I've ever seen AC with it but they do make MC with an outer plastic covering that is listed for wet locations and direct burial but it is only available in larger conductor sizes.

Normal AC and MC is dry locations only. Always has.

-Hal
We have jacketed MC available in this area in 14,12, 10, etc. (actually have a 16ga for mini-splits)
 

infinity

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Location
New Jersey
Occupation
Journeyman Electrician
It was permitted at one time for regular MC if it had wet location conductors. This is from the 2005 NEC.

330.10(A) General Uses Type MC cable shall be permitted as follows:
(1) For services, feeders, and branch circuits
(2) For power, lighting, control, and signal circuits
(3) Indoors or outdoors
(4) Exposed or concealed
(5) To be direct buried where identified for such use
(6) In cable tray where identified for such use
(7) In any raceway
(8) As aerial cable on a messenger
(9) In hazardous (classified) locations as permitted
(10) In dry locations and embedded in plaster finish on brick or other masonry except
in damp or wet locations
(11) In wet locations where any of the following conditions are met:
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
(5) To be direct buried where identified for such use
(11) In wet locations where any of the following conditions are met:

What are those conditions?

I think the NEC was evolving back then on the use of MC. I remember too that there was a solid sheath MC. I'm thinking that they were trying to cover all the kinds of MC in one article with the blanket "where identified for such use". So I don't think the NEC is going to be any help and, to really settle this I think someone has to come up with the a manufacturers information for an armored MC listed for wet locations like the OP has.

-Hal
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
(5) To be direct buried where identified for such use
(11) In wet locations where any of the following conditions are met:

What are those conditions?

I think the NEC was evolving back then on the use of MC. I remember too that there was a solid sheath MC. I'm thinking that they were trying to cover all the kinds of MC in one article with the blanket "where identified for such use". So I don't think the NEC is going to be any help and, to really settle this I think someone has to come up with the a manufacturers information for an armored MC listed for wet locations like the OP has.

-Hal

Are you asking a separate question about (5)? The OP is asking about a wet location on the roof so that would fall under 330.10(A)(3)&(11).
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Old building with MC cable running on roof feeding lights. Probably 20+ years old. Thank you for your help.
Short answer you will need to figure out the year it was built/permitted and figure out the exact cable type. ACL and ALS were allowed outdoors.
Longer answer:
The 1928 NEC 505j mentions a type of AC called ACL cable that has a lead sheath under the armor that can be used outdoors or underground. The cable was last listed in the 1990 edition. The lead sheath under the armor makes the cable really heavy, is very noticeable when doing demo and of course workers should use caution demoing it (Cutting it with a sawsall should be avoided).
In the 1959 NEC type AC was first required to have that bonding strip in it, so you can date a system by looking for that strip.
In the 1962 NEC a new Article was added for Aluminum-Sheathed Cable type ALS cable (MC also first appeared in the code in 1962 when Article 334 got renamed after it).
ALS cable seems like the aluminum MC we often see today as 'MC-Lite' the 1962 331-2 allowed ALS in dry or wet locations ( but no corrosive)
Perhaps someone whom worked with ALS cable in the early 70's can chime in?
ALS continued up to the 1975 NEC when the article got deleted.
The 1978 NEC split MC and AC into different articles.
Cheers
 
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