# Junction box wrong shape/size for light



## TrpnBils

I'm installing a new outdoor light on the house (replacing a single flood with a motion sensor security light). I didn't realize until I took the old one off the house today that it's got a small rectangular junction box. The brackets that came with the new (round-based) light won't even fit in there. Is there any kind of adapter you can get, or is it a DIY kind of thing?

My biggest concern is keeping insects and water out of there. It's under the overhang, but I'd rather keep it sealed well if I can.


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## JulieMor

Yes, there are ring adapters that can handle most any application. They are pretty common. I know Home Depot has them.


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## andrew79

it's probably not a good idea to rig up a fixture designed for an octagon box to fit into a receptacle box(assuming from rectangular description) depending on the wall finish and whatnot it's probably best to switch out the box for the right one. Don't have time to dig out a code book but if it is indeed a receptacle box easiest way to fix would be to get a rab box and mount it surface. Use the knockout in the back to put a chase nipple into the receptacle box. Bring your wires out through the chase and make sure the rab box is well sealed to the wall with an outdoor silicone. You now have your octagon box you need for mounting and they are available in different colours so you can match your light so it doesn't look wierd. 
Anyone out there with a codebook handy feel free to chime in and let me know if this is even legal lol.

If it's a 4 inch square box then as the above poster stated just run to home depot and grab an octagon plaster ring for it.


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## jbfan

I don't think he is talking about a plaster ring.
Some lights come with the bars that allow you to mount the lights level, but other lights have a round plate with slots.
I think this is the plate he is talking about.


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## JulieMor

If the box looks like this 








you can use something like this 








or this 








depending on the new fixture canopy mounting requirements. 

There's also a ring that has slots and threaded holes that is pretty universal. It can be mounted to either round or rectangular boxes and fits most any fixture that has two screw mountings. (ignore the pan box in the image)


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## andrew79

i can see doing it on an octagon box but how does any of those actually prevent leaking if installed in an 1104 box. I've never seen it done on a house here(that doesn't mean it hasn't been :laughing: ). Both those adapters are designed to fit octagon boxes, good to know they fit receptacle boxes as well. Always learn something new around here. I doubt there's actually a code reference for it from either the u.s or canada. I guess safety wise it'll work just fine if you caulk it. Be interested to know if there actually is a rule on what type of box you can use for a light, guess that means digging up my dreaded code book.


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## andrew79

i actually found the nec rule on google lol. As long as it's not over 6 lbs you can use a receptacle box for wall mounting if it's held by not less than 2 6-32 screws. ceilings are a no no.


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## JulieMor

The reality is fixtures usually come with adapter brackets and, if needed, we electricians usually use those when we hang the fixtures. In all my years I've never even heard a mention about the brackets relating to code or not passing an inspection. The only thing I've heard from some inspectors is the fixture has to be UL and/or CSA approved. A few pressure you into fixtures being union made too.

There are a few guys in my local who are code gurus. They study the thing constantly. When they are on your job, you will hear them preach code with fire and brimstone. Any time they see ANYTHING against code, they will let you know. And even they have been silent on fixture brackets.

Andrew, until you mentioned it here, I've never even heard a peep about the code addressing brackets in any way. Maybe the fact that inspectors check the rough in, the wire pull and then the finished product and never see the mounting brackets, they just fell off the radar.


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## k_buz

You know how many ceiling mount fixtures I've installed on 4 square bracket boxes with 1/g plaster rings? Too many too count.:whistling2:


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## JulieMor

k_buz said:


> You know how many ceiling mount fixtures I've installed on 4 square bracket boxes with 1/g plaster rings? Too many too count.:whistling2:


Here, we're only allowed three conduits in an octagonal box, so if you have four conduits in a ceiling box that will feed a fixture, guess what we are required to do? And that's code here.

What always blew my mind was when a heavy fixture (maybe 30+ lbs) came out to the job and the mounting screws were (2) 8-32. On the heaviest (say 40-50 lbs and over), the manufacturer added a cable that was supposed to be attached directly to the electrical box. So when the screws failed, the cable would stop the fixture from falling to the floor. :huh: Nice design.


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## andrew79

It's not a common practice here in canada at all. I got lucky when i googled it and that popped up. The 4 inch square with plaster ring is ok for ceiling mounts according the the rule i found the other day as it uses 8-32's for supports. It's only for 6-32's(receptacle box screws). I'd get laughed off the job if i put one of those brackets on a receptacle box lol(hence my sort of confused response). The differences in what is considered ok between us and the states never ceases to amaze me. It's not that we're always stricter, there's many parts of the NEC i feel are superior to the the CEC and vice versa. But hey what do i know, us lowly electricians are just peons to the rulemakers :laughing:


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## ohman

I found this thread because I did a search with motion sensor light junction box. I have a size related question that I want to ask which I hope can add to the discussion/knowledge base and won't hijack this thread. If you feel that I should start a new thread please let me know and I would do just that...

Does most *Heath-Zenith* motion sensor lights share the same size of junction box? I tried to read their installation guide manual PDF files (for SL4150 *decorative *wall-mounted model and the typical garage motion sensor light like SL-5412). They look like using the same size of junction box but from the manual I can't really tell. Thanks!


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## jbfan

ohman said:


> I found this thread because I did a search with motion sensor light junction box. I have a size related question that I want to ask which I hope can add to the discussion/knowledge base and won't hijack this thread. If you feel that I should start a new thread please let me know and I would do just that...
> 
> Does most *Heath-Zenith* motion sensor lights share the same size of junction box? I tried to read their installation guide manual PDF files (for SL4150 *decorative *wall-mounted model and the typical garage motion sensor light like SL-5412). They look like using the same size of junction box but from the manual I can't really tell. Thanks!


All Outdoor lights I have used will fit a round box, or a rectangular box.


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