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Re: 4" round plastic box

Posted By: harold endean

Re: 4" round plastic box - 05/16/11 01:50 PM

An electrical contractor told me about plastic 4" round ceiling boxes. He said that in order to be rated for 50 lbs. you had to install a screw in the box and attach it to the ceiling joist. I asked him, OK where does it say that? and he said he the last AHJ told him.

Now I don't know if it was true or not, and I was trying to find something on either Slater or Carlon website, but all I found is that those boxes are rated for 50lbs. I tried to find installation instructions, but nothing was written there either.
Anyone heard this before?
Posted By: gfretwell

Re: 4" round plastic box - 05/16/11 05:30 PM

I don't see anything that says that either.
Is he saying you need to drill a hole in the side of the box and install an additional screw?
Posted By: Bill Addiss

Re: 4" round plastic box - 05/16/11 06:36 PM

It's been awhile, but this sounds somewhat familiar... Some Boxes are supposed to be for Fans, but say the Fan has to be supported indepentantly of the Outlet Box (screw through Box). Maybe that's what he means?

I found the following for one Brand:

Quote
Weight Limits: Fans and fixtures are supported independent of outlet box. Mounting screws go through box and into joist.
Box will support up to 70 lbs. for fans and 90 lbs. for fixtures.


This sounds a bit misleading, as the box isn't actually supporting anything if the mounting screws go into the joist.

http://www.cooperindustries.com/con...iling%20Fan%20Boxes%20and%20Supports.pdf

Bill
Posted By: HotLine1

Re: 4" round plastic box - 05/16/11 07:16 PM

Harold:
Do you mean the TP 16511 in Bills link??

The TP 1300 or equal by other mfg does allow the fan support hardware to be attached direct to framing. The TP 16511 type is a nail-on & 35# rated, and I know of no provisions to 'attach' any type of fan braces to that box.

I'm quite sure that some enterprising person could mount a 2x? over the top of the box & run lags/screws into that but ...bye, bye listing.

Posted By: gfretwell

Re: 4" round plastic box - 05/16/11 10:59 PM

The fan boxes I see are nailed/screwed to the side of the joist and the only real difference I see is the mounting screws are #10 and they extend through the ears to the back of the box. I may have one here somewhere.
I see nothing in the white book that indicates any more support is required than what is provided by the supplied mounting bar or bracket.
Posted By: Obsaleet

Re: 4" round plastic box - 05/17/11 03:42 AM


How about Allied boxes or Smart boxes. Smart boxes are advertised on this site.

http://www.alliedmoulded.com/index....template/products_sub_res/categoryid/222

http://www.licensedelectrician.com/Store/SmartBox.htm

Ob
Posted By: Bill Addiss

Re: 4" round plastic box - 05/17/11 04:51 AM

Originally Posted by Obsaleet

... Smart boxes are advertised on this site.

http://www.licensedelectrician.com/Store/SmartBox.htm

Ob

You can't tell from the picture of this Box, but there is a heavy metal plate that goes behind the area that screws to the ceiling joist and across the top of the box to support the fan itself. These are not your average plastic fan boxes by a longshot.

You can see it by clicking on the 'New Release' picture under the Box on page below:

http://www.licensedelectrician.com/Store/SmartBox-3.htm

Bill
Posted By: dougwells

Re: 4" round plastic box - 05/17/11 06:08 AM

I never knew that a paddle fan receiver could fit inside the box , cool idea
Posted By: harold endean

Re: 4" round plastic box - 05/18/11 02:25 PM

No to all the above. The box I saw was a black box that looked like Slater I think. The EC on the job told me that he failed in another town because he did not have the screw there. He said the OTHER AHJ told him that it had to be installed. He said something to the effect, "When there isn't a screw there the box is only rated for 30 lbs' , but when you have the screw, it is good for 50lbs."

Now I know this other AHJ and he is a nit picker. He likes fail guys for anything that he can. He usually does his homework and finds out small details with which to fail you. However I think that sometimes he will stretch a point just to be able to give you a red sticker.

So when this EC looked to me for some guidance, I told him that I would look into it. I have seen the boxes and they do have a small hole in the top where a screw could fit through and hit the rafter. I just can't seem to find more info on the matter.
Posted By: gfretwell

Re: 4" round plastic box - 05/18/11 05:20 PM

This sounds like a question for the manufacturer. They are the ones who did all of the engineering to certify that their boxes are 50 lb rated. I looked at several pages and I did not see anything that indicated that you needed any more than the fasteners in the mounting bracket. The ones with the 2 captive nails seem to be 50lb rated.
Posted By: HotLine1

Re: 4" round plastic box - 05/18/11 07:14 PM

Greg:
The 'blue' (Carlon) with captive nails has a 50# listing for fixtures. I see no reference to 'fans'.

IMHO, using the above & inserting a 'hanging' screw/hook/etc. thru the box don't fly.

Posted By: gfretwell

Re: 4" round plastic box - 05/18/11 10:13 PM

They do have a blue fan box (35lb max) but I don't see how it is mounted. It may be "up" through the framing
Posted By: Tesla

Re: 4" round plastic box - 05/18/11 11:08 PM

The screws included in fan-rated box kits are NOT standard run-of-the-mill screws. They are extra strong and a tad longer.

I'm speaking of the metallic boxes.

Going plastic for fan boxes is not very appealing to me.

BTW, watch out for the whip antenna... it needs to stay outside any 'Faraday cage' created by metallic boxes.
Posted By: gfretwell

Re: 4" round plastic box - 05/19/11 02:25 AM

I thought the only thing special about a fan box screw is it had to be #10 and extend from the structure of the box, not the mounting ears.
Posted By: HotLine1

Re: 4" round plastic box - 05/19/11 03:17 AM

Greg:
I think he is refering to the 'longer' #10 machine screws and metal boxes. A few metal fan boxes have heavy metal bosses from face of box to back of box for fan mounting plates.
Posted By: gfretwell

Re: 4" round plastic box - 05/19/11 05:51 PM

The ones I have seen just thread the 10-32 screw into the back of, what appears to be, a normal octagon box. They go through the ears unattached, only using them for alignment.
I can see why this is a lot stronger but it is more geometry than the strength of the material.
Posted By: Niko

Re: 4" round plastic box - 05/22/11 07:50 PM

I checked on carlon's site and as Greg mentioned the round boxes with the mounting nails are rated for 50lbs. it doesn't mention anything about additional screws. But the box itself doesn't have the weight rating on it but it is listed on their site.

On a second note, the same exact box with the same part # but with a sticker on it that shows the wight rating, sells for 4 times more.
Posted By: gfretwell

Re: 4" round plastic box - 05/22/11 09:22 PM

"Insurance" wink
Posted By: LEO_304E

Re: 4" round plastic box - 05/22/11 09:50 PM

Originally Posted by Tesla
The screws included in fan-rated box kits are NOT standard run-of-the-mill screws. They are extra strong and a tad longer.

I'm speaking of the metallic boxes.

Going plastic for fan boxes is not very appealing to me.

BTW, watch out for the whip antenna... it needs to stay outside any 'Faraday cage' created by metallic boxes.


I like the metal boxes better allso.. rolleyes
Posted By: KJay

Re: 4" round plastic box - 05/23/11 03:33 AM

I have some standard T&B nail on plastic ceiling boxes that have two holes in the top of them, but the holes are for bar hanger screws. The only reason I know this is because I also have the T&B plastic ceiling boxes with bar hangers and they just use the exact same mold for all of these boxes. They even have the nail holder ears molded on the bar hanger boxes, just with no nails included.
Posted By: harold endean

Re: 4" round plastic box - 05/29/11 02:14 AM

Sorry, I have been very busy the past few days. I couldn't get back here. I think this is a case of an AHJ making up his own rules again. I have yet to find any reference to adding hardware, screws etc. in order to make a plastic box suitable for 50 lbs.
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