Weight rating 4 square boxes

[ttjangu]

Can someone please clarify the 50 pound rating for fixtures and the appropriate box when using mud rings. I cannot get a weght rating on a 4 square bracket box but mud rings designed for luminaires do show the 50 lb rating. What I am questioning is can a 4 square bracket box be used on a ceiling rafter/ joist for lighting when the appropriate mud ring is attached? Recently an inspector questioned this use because the box itself has no weight rating on it and I cannot find a manufacturer that has one.

 

[cburke1111]

Good question. I'm interested in finding the answer to.

Sent from my Pixel 2 XL using Tapatalk

 

[LarryFine]

The weak link would be the 8-32 box/cover screws. As the 50lb rating is usually assigned to fixture boxes and fixture mounting straps that use 8-32's, that's what I would go by, and offer to the inspector.

 

[MAC702]

The weak link would be the 8-32 box/cover screws. ...

I was thinking it would be the bracket attachment to the joist, which could exceed the rating or not depending on method. But I'm open to be convinced either way.

I've repaired situations where ceiling fans were falling from not being installed on fan-rated boxes. The failures were from the brackets coming off the joist, not the mud ring or fan bracket screws. Granted, this is a fan load, and not a static load, but it's where I've seen the failures. And these were much older bracket boxes and methods than are common now.

 

[LarryFine]

The box-to-joist mounting for fixtures and for fans is obviously different, as the mounting method as part of the fan box's rating. I have also seen fixture boxes detached by fans, but never by fixtures.

 

[JFletcher]

A standard 1900 box with or without ears is not going to have a weight rating. Not sure why you'd want to use a square box and mud ring over around box anyway but you need to look into boxes for fan use that have least the 50 pound rating, you can also look into pancake boxes and those by Arlington that are made to go directly on the joist and have the box volume up beside it. if you have a wonky ceiling detail where you need a 2-inch ring or something, I would check with Arlington first.

I'm not sure but something like a caddy TSB 16 or 24 bracket it's not going to work either, I've only ever seen those installed for vertical box applications, I do not believe they have a weight rating

 

[jumper]

I did not find a weight rating for a standard 4” square box but a a Hubble 4” octagon has a 50 lb weight rating per manufacturer. Besides shape, I see no real difference between them. Both use 8-32 screws for attaching devices/fixtures.

https://www.hubbell.com/hubbell/en/...onic/Boxes/Ceiling-Boxes-Covers/125/p/1670069

 

[MAC702]

I did not find a weight rating for a standard 4” square box but a a Hubble 4” octagon has a 50 lb weight rating ...

I would venture the bracket part of the 4" bracket box is going to be the real issue.

 

[jumper]

I would venture the bracket part of the 4" bracket box is going to be the real issue.

What is a bracket box? Box with a bracket/strap for mounting?

 

[MAC702]

That is what I've always known as a "4 square bracket box," yes.

 

[K8MHZ]

Hubble shows octagonal boxes with brackets with 50 lb. ratings.

https://www.hubbell.com/hubbell/en/...onic/Boxes/Ceiling-Boxes-Covers/119/p/1670068

I think the issue is that 4 squares are not considered to be ceiling boxes and thus have no weight rating. That's how it looks on the Hubble web site, anyway.

 

[jumper]

Hubble shows octagonal boxes with brackets with 50 lb. ratings.

https://www.hubbell.com/hubbell/en/...onic/Boxes/Ceiling-Boxes-Covers/119/p/1670068

I think the issue is that 4 squares are not considered to be ceiling boxes and thus have no weight rating. That's how it looks on the Hubble web site, anyway.

Uh Kate.....

See post #7:angel:

 

[Little Bill]

Uh Kate.....

See post #7:angel:

I saw it, it's between #6 & #8!

 

[jumper]

I saw it, it's between #6 & #8!

The proper Southern term is “twixt”. Jeez....

 

[K8MHZ]

Uh Kate.....

See post #7:angel:

I did see it. My statement still stands. I seems that 4 squares are not considered to be ceiling boxes by the manufacturer and thus no need for a fixture weight rating.

 

[jumper]

I did see it. My statement still stands. I seems that 4 squares are not considered to be ceiling boxes by the manufacturer and thus no need for a fixture weight rating.

Agree.

 

[hbiss]

Isn't it prohibited to have the 8/32 box screws support the fan in any case? Isn't the fan supposed to be supported by larger screws independently of the box? That's the jist of the design for any fan box.

I think that regardless of what box you use, if you could support the fan from the structure independently of the box you would be OK.

-Hal

 

[rambojoe]

it isnt exactly what the op asked, but the differance aside from the machine screw size is a (metal) fan box screw threads into the back of the box, not the little tangs- and of course 10-24 screws (iirc... 10-32?) oh... and they (most) seem to be forged, not spot welded like 4sq origami jobs..

 

[Adamjamma]

Carlons Plastic boxes are rated 50 lbs for ceiling use.. or at least the ENT style ones are...

Know not many people are using them, with the mud rings etc...

 

[jumper]

Isn't it prohibited to have the 8/32 box screws support the fan in any case? Isn't the fan supposed to be supported by larger screws independently of the box? That's the jist of the design for any fan box.

I think that regardless of what box you use, if you could support the fan from the structure independently of the box you would be OK.

-Hal

it isnt exactly what the op asked, but the differance aside from the machine screw size is a (metal) fan box screw threads into the back of the box, not the little tangs- and of course 10-24 screws (iirc... 10-32?) oh... and they (most) seem to be forged, not spot welded like 4sq origami jobs..

Who said anything about a fan box?