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#90183 - 11/02/04 06:14 AM What are "moderate degrees" of moisture?
Joe Tedesco Offline
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Registered: 10/07/00
Posts: 2749
Loc: Boston, Massachusetts USA
Quote:
Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.


Question from a Student today:

How can one quantify, or determine the moderate degree of moisture present?

[This message has been edited by Joe Tedesco (edited 11-02-2004).]
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#90184 - 11/02/04 08:09 AM Re: What are "moderate degrees" of moisture?
John Steinke Offline
Member
Registered: 04/03/01
Posts: 518
Loc: Reno,Nv., USA
It always seemed obvious to me that areas not directly exposed to weather or spray would be "damp." Later, I was taught that "damp" was the area covered by a 45 degree imaginary line from the end of an eave, canopy, etc.
Another "damp" indicator was the likelihood of condensation forming- as in basements and crawl spaces.
Darned if I can document these things, though.
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#90185 - 11/02/04 01:10 PM Re: What are "moderate degrees" of moisture?
George Little Offline
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Registered: 01/18/04
Posts: 1488
Loc: Michigan USA
I guess I don't get your point Joe, moderate degree or low degree or high degree is still moisture. So what ever the requirements are for a moist environment (also defined as wet by Websters) the rules apply. Little bit like being partially pregnant, no such thing. Moisture is defined also as "small amoint of liquid that cause dampness"
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#90186 - 11/02/04 11:01 PM Re: What are "moderate degrees" of moisture?
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
I imagine he is talking about language like 334.12(A)(10)(d)d. Where exposed or subject to excessive moisture or dampness.


What is excessive for a wiring method that is permitted for "damp" locations?

334.(10)(B) Type NMC. Type NMC cable shall be permitted as follows:
(1) For both exposed and concealed work in dry, moist, damp, or corrosive locations,
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#90187 - 11/03/04 11:31 AM Re: What are "moderate degrees" of moisture?
ElectricAL Offline
Member
Registered: 10/10/01
Posts: 597
Loc: Minneapolis, MN USA
Quote:
by George Little:
Little bit like being partially pregnant, no such thing.
The dew and frost that appears on your windshield is "wet" but it disappears when the sun comes up. The baby doesn't.

When the temperature of a material swings below and above the atmospheric dew point, the "wet" moisture will appear and disappear. Damp Locations are not subject to "saturation".
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#90188 - 11/03/04 05:30 PM Re: What are "moderate degrees" of moisture?
John Steinke Offline
Member
Registered: 04/03/01
Posts: 518
Loc: Reno,Nv., USA
I looked at the UL "White Book," as I recall the days before UL honored NEMA ratings.
"Damp" defined in part as 'partially protected under canopies' or 'locations subject to moderate degrees of moisture.'
"Wet" described as 'underground,' 'subject to saturation,' or 'exposed unprotected to weather.'

"Dry," incidentally, "may be temporarily subject to wetness."

It is also relevant that UL also notes that, in some cases, the title of the equipment indicates the conditions appropriate for the item.

Information found in the first pages of the "White Book". This is also quoted in the NEC Handbook.
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