1/4" space in wet location

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iggy2

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NEw England
I recall, but cannot find, a requirement to space boxes and conduits off the wall by 1/4" in wet locations.

Can anyone point me there? I've spent an hour or so googling, and have searched NFPA 70-2014 but not found it.....

Thanks.
 
Here is the art.

312.2 Damp and Wet Locations. In damp or wet locations,
surface-type enclosures within the scope of this article
shall be placed or equipped so as to prevent moisture
or water from entering and accumulating within the cabinet
or cutout box, and shall be mounted so there is at least
6-mm (1?4-in.) airspace between the enclosure and the wall
or other supporting surface. Enclosures installed in wet locations
shall be weatherproof. For enclosures in wet locations,
raceways or cables entering above the level of uninsulated
live parts shall use fittings listed for wet locations.
Exception: Nonmetallic enclosures shall be permitted to
be installed without the airspace on a concrete, masonry,
tile, or similar surface
 
Thanks.

I guess I cannot require the 1/4" space for a conduit unless indoors per 300.6. An outdoor RGS conduit on a brick wall need not be spaced off the wall.

and 312.2 applies to cabinets and meters, not raceways.

Thanks for the replies.
 
Now install it in a food processing place or other place where sanitary conditions rule and they will caulk around it even if you left a 1/4 space behind it. 1/4 is not enough for them to assure things do not accumulate behind there and they would rather have that space completely sealed then to house bacterial growth behind there.
 
We all know 1/4" is requirement but how many of us do install with the minimum spacing?

I know I don't. Unless the enclosure comes with a 1/4" back side dimples that will allow 1/4" spacing, other than that all of the conduits, bell boxes..... go right on the wall.
 
We all know 1/4" is requirement but how many of us do install with the minimum spacing?

I know I don't. Unless the enclosure comes with a 1/4" back side dimples that will allow 1/4" spacing, other than that all of the conduits, bell boxes..... go right on the wall.

When did you last purchase a type 3R or higher number that did not have back dimples or mounting feet that provided the spacing?

How often have you mounted an enclosure via other mounting means?

How often have you mounted an enclosure on an uneven surface and this spacing meant nothing?

This is a rule in there that is often overlooked, but design of products does help with compliance - but only on a smooth flat surface.
 
When did you last purchase a type 3R or higher number that did not have back dimples or mounting feet that provided the spacing? THEY all come with the dimples. Except the bell boxes.

How often have you mounted an enclosure via other mounting means? NO

How often have you mounted an enclosure on an uneven surface and this spacing meant nothing? I usually create my own flat surface.

This is a rule in there that is often overlooked, but design of products does help with compliance - but only on a smooth flat surface.


I thought there was a wording somewhere that required ALL of the equipment (enclosures, boxes, conduit....) that was installed in a wet location must have 1/4" spacing. Did that get deleted for 2011 OR 2014?
 
300.6(D) in the 2014 book

Also look at 312.2

I thought there was a wording somewhere that required ALL of the equipment (enclosures, boxes, conduit....) that was installed in a wet location must have 1/4" spacing. Did that get deleted for 2011 OR 2014?
I don't think this has changed much in some time. Read each mentioned carefully, though similar they are not the same.

300.6(D) is talking about all parts of the wiring system in indoor places that are washed frequently like dairies, canneries, etc. exception is for nonmetallic raceways, boxes, etc. and they probably should include stainless equipment as well but they didn't. Then the informational note explains some reasons why this is required.

312.2 would only apply to cabinets, cutout boxes and meter sockets, exception again for non metallic. Informational note does refer you to 300.6 though -but that is informational only and not a requirement.

Again like I said earlier in the dairies, canneries, etc. where sanitation is a big issue, 1/4 inch isn't really enough gap behind a larger enclosure, crud builds up behind there and bacterial growth is a problem - bad for a sanitary operation. If there isn't enough space to inspect the gap for cleanliness from my experience they will caulk that gap and eliminate the material buildup and bacterial growth issues, it makes their sanitary inspections go much easier. So does having raceways spaced off walls even if they are non metallic, stainless, or otherwise corrosion resistant, they are easier to keep clean when spaced off the walls - especially horizontal runs - which should be avoided whenever possible in these areas.
 
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