Impropper outside wiring

**Bob Sisson** · 07-09-2012, 08:41 AM

I would like to start a discussion about improper outside wiring.

I inspected a house the other day with homeowner installed under deck lights that used ROMEX style wire clamps on a Red-Dot box. It was also missing a plug and had a wasp nest inside. When the seller had an "electrician" (please note my quotes) look at it, he asked "What does he say is wrong with it, looks fine to me..."

Am I wrong to think that the example on the left is WRONG for outdoor wiring? I was trained that you needed the weather tight clamp as on the right for outdoor stuff...(And yes, I used the wrong wire in my example, couldn't find a scrap of outdoor 12/2)

I have seen these boxes dripping water after a rain because they used the wrong clamps, didn't fill the holes, didn't use the gaskets and more... We won't mention what the OTHER end looks like...or that they are rarely on a GFCI circuit... And yes, I have seen indoor blue boxes, new work boxes, utility boxes, and just about everything else used... but the people who use the Red-Dot boxes think all they need to use is an outdoor type box and outdoor wire....

Comments, thoughts, example from your libraries? What would you write?

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Garry Blankenship · 07-09-2012, 08:57 AM

You're going to get plenty of input. I'm not willing to cite the specific NEC references, but the issues I see are: Romex / NM is not approved for wet locations. It cannot be subject to physical damage, but can be used on the surface in allowable situations. NM cable aside; the fittings must also be approved, ( U/L listed ) for outdoor use. Fittings allowed for outdoor use are either gasketed or use a compression ring that discourages the travel of water. When wiring outdoor the entire system, ( boxes, fittings, raceway / conductors and devices / fixtures ), must be listed for the application.

**Jim Port** · 07-09-2012, 02:47 PM

What was the orientation of the box? I see no issues with the indoor clamp on the box if the box is vetical and the clamp is on the bottom. Water is not going to leak up. Now is the orientation is as shown the proper clamp with the sealing grommet would need to be used.

**Bob Sisson** · 07-09-2012, 04:40 PM

Everybody seems to think that water doesn't go uphill, it sure does...wind driven rain goes everywhere...combine capillary action and surface tension and it doesn't matter where it is, if it has the wrong fitting, water will flow in...

The compression gasket fittings also help to keep out ants, which seem to LOVE electrical things, especially older GFCI receptacles...
..

**Jerry Peck** · 07-09-2012, 04:54 PM

Not only is that regular NM cable clamp NOT allowed to be used outdoors (because it is not listed for use in wet locations) ... but ... NM cable is not allowed to be used outdoors either.

The cable in the right photo showing the compression fitting looks to be NM cable and not UF cable - do not use NM cable outside as it is not listed for use in wet locations either (NM cable is also not sunlight resistant either, which does not matter because it is not allowed to be used in wet OR EVEN DAMP locations.

**Jerry Peck** · 07-09-2012, 05:15 PM

Originally Posted by Jim Port

What was the orientation of the box? I see no issues with the indoor clamp on the box if the box is vetical and the clamp is on the bottom. Water is not going to leak up. Now is the orientation is as shown the proper clamp with the sealing grommet would need to be used.

The orientation does not matter, the location does, and if it is outdoors it is a wet location (unless well protected by an overhang):
- 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.

Unless well protected as stated above, if it is outdoors it is a wet location, and in wet locations the fittings need to be - as Robert posted and pointed out: "fittings installed in wet locations shall be listed for use in wet locations"

**Bob Sisson** · 07-09-2012, 05:51 PM

I am glad lots of people also caught the NM wire, I know it is supposed to be UF, but like many handy people putting lights under decks, I didn't have a piece to make my example for the picture.

What is slightly anoying is there -are- some older white outdoor cables...the only way to identify them is to look for the "Sunlight resistant" written on the side....Most of that stuff is pretty brittle and degraded by now though...some is due for replacement even if it is the right stuff... Not sure if it is really "outdoor UF" or just "sunlight resistant" as all of the stuff I have seen was really really faded and I couldn't see the ends to see if it had any paper inside...

**Jim Port** · 07-11-2012, 05:48 AM

Originally Posted by Robert Meier

Although you're correct that it probably wouldn't be an issue the NEC would require a wet location connector even on the bottom of the box if installed in a wet location. If this were a meter enclosure or cabinet then you're correct a squeeze connector on the bottom would be compliant.

Kind of ironic that you can use an indoor clamp on SE cable into an enclosure but can't do the same thing on UF into an FS box.