Box Type for Flush Mounted Exterior Light


Old 09-21-01, 05:21 AM
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I want to place a floodlight fixture on the exterior wall of my basement. The outside is vinyl siding over celotex type material. Inside is as of yet unfinished 2x4 framing. The fixture that I place on the siding is flush mounted and will fit on a rectangular box. Do I need a specially constructed box, or can I just use a standard gray plastic type and silicone seal it?

(My perception is the gray is tougher than the somewhat flexible blue..?)

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Old 09-21-01, 10:31 AM
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You have a few problems with your installation. One problem is installing a box that will land on the flat of the siding and then if you to get a box landing on the flat of the vinyl siding then you find the siding not stiff enough to cause an affective seal to keep the water out.

You could use a round plastic light box with wings and make a decent mount landing where you desire yet you still have that sealing problem involved.

If it were me I would spend the extra dollars and buy a metal surface mount round weather proof light box using toggal bolts to mount the box to the wall with the cable entering that box with a connector mounted on the back of that box hiding that cable when the box is mounted. YOu should find the round metal w/p light box to be the same diameter as the base of the flood fixture allowing a good seal. As you mount the box to the wall a dab of sealant on the screw holes throught the siding should seal those holes also.

If you have open studs inside that wall you could nail a 2x4 nailer accross the two studs where you want to mount the light then drill a hole through that 2x4 nailer and run your cable through the naile into the w/p metal light box surface mounted. Then use wood screws to mount the box to the wall making a solid mount for the fixture.

Another comment as an experiment the blue plastic box that you talked of showning doubt of its strength buy one and try to burn it, cut it, tear it apart, rip the threads out of it so that they can not be reused. You should find your work cut out for you. Those plastic boxes are way more solid in strength than they look.

I know of a home wired with plastic boxes including the blue box you spoke of and the bakelite box also that were mounted in the wall. Lightening struck strong enough to blow the entire wall off the end of that home where those boxes were mounted. The TV picture tube blew to the point of glass sticking in the wall across the room. Nails were pulled through the top plate then through the studs throughout the home and welded to the romex where that romex passed close to those nails. The ground rod melted where it was originally mounted. The wall that was blown apart and totally gone except splinters was where the couple were sleeping. They had a rude awakening but was not hurt in the least. Guess what those non metallic boxes both bakelite and blue plastic were blown off the studs they were mounted to but they were not damaged beyond reusing them if you wished. They had some burn marks on them and some scratches but were otherwise still intact.

Try the experiment and take your bare hands or even a couple of pairs of pliers and try tearing one apart. Even overtighten the threads to the point of stripping out the threads. Then back out the screw and rescrew that screw back in place the device will still be held by those damaged threads. You will be worn out but the box will be ready to be used experiencing little damage.

Let us know what you find out in that experiment. You might be surprised how strong those nonmetallic boxes are. The bakelite will break if struck with a hammer especially in cold weather, otherwise they will hold up better than you think. Best of all they are not a conductor of electricity thus acting as a double insulation product.

Seems safe to me, try it you should be pleasantly surprised.

Good Luck

Old 09-21-01, 12:58 PM
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I am partial to these ;
Old 09-21-01, 02:58 PM
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Wirenuts, that product is a great product. The only problem I see with this product is what I am experiencing in my jurisdiction. Electricians are convinced in this area that a box does not need to be installed with this product. They are convinced that this product is approved for use in place of a box. Several inspectors in this area are having fits convincing these electricians that boxes are required. I loved the link showing installation instructions. Boy am I going to use that link in my emails around here.


Old 09-21-01, 11:13 PM
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I'm sure you've gone by homes and seen fixtures mounted directly to the clapboard, cocked off, the gaps from the siding laps big enough for any hornet's desire?

It's always been a pet peeve of mine , looks real bad. As i am currently a 'romex jockey' again wiring new homes i'll ask for blocks to be placed around steel octogons. But on renovations i'll use these arlington jobs. Theses are NOT listed for use as a box , but there are varieties that are listed and rated as the enclosure also .
Old 09-22-01, 03:12 AM
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Wirenuts, the link you provided has installation instructions requiring a box. I am not aware of one of these products to be used as a box. Can you provide me that link showing installation instructions where they are approved for use in place of a box?

Curious, may learn something here

Old 09-22-01, 03:24 AM
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Wirenuts, I found that I didn't look far enough into the site. I found the one you were talking of at
Now all I have to do is get those wiring in my jurisdiction to start using these instead of the ones that require the box they are not installing with their installation. Thanks for your link. Now to get our suppliers to stock the blocks approved for use as a box itself.


Old 09-22-01, 04:25 AM
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by golly you did find one! i have'nt used those as yet, guess i'm still skeptical, if anyone out there have had any experience with these i am curious....


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