Will A Nail Up Light Box Actually Support A 50Lb. Light?

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Ravenvalor

Senior Member
Greetings and Happy 2021.

I just installed a 50Lb. chandelier onto a fiber type nail up light box. Does anyone on this forum have any experience with a nail up light box rated 50Lbs. that did not adequately support a 50Lb. light? I used 4 - 8/32 screws to attach the light to the box because I have one time encountered a light that was so heavy it broke the screw holes sections of the fiber type nail up light box. The box is the brown fiber type that was manufactured in the 90's.

Thanks,
 

kwired

Electron manager
Location
NE Nebraska
If you have a 50lb fixture, why wouldn't you go with a higher rated box? Also, if you're using old material, I wouldn't advise that either.
My guess existing installation and the box is already there?

If it is a nail on box then it is right next to a framing member of some sort, if you can't access back side cut nails with sawzall blade, remove plastic box and replace with one of those retrofit ceiling fan bracket boxes that mounts to side of a framing member or even one with an extension bar to go between framing members.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
My guess existing installation and the box is already there?

If it is a nail on box then it is right next to a framing member of some sort, if you can't access back side cut nails with sawzall blade, remove plastic box and replace with one of those retrofit ceiling fan bracket boxes that mounts to side of a framing member or even one with an extension bar to go between framing members.
Did you mean "if you CAN access back side........." instead of can't?
 

kwired

Electron manager
Location
NE Nebraska
Did you mean "if you CAN access back side........." instead of can't?
I meant can't access back side, in that case you have to use "through the hole" methods like I mentioned if you don't want to have to repair the ceiling finish - or take the risk that the non metallic box will not give up sometime down the road.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I just installed a 50Lb. chandelier onto a fiber type nail up light box.
I wouldn't have. I use fan boxes for heavy fixtures. For the last two really heavy lights we hung we used fan boxes and two fixture straps in an X shape, one held by the 8-32s, one by the fan screws.

And yes, the side-mount retro box kit is the way to go for replacing nail-on boxes. Note the hole may need to be enlarged by about 1/2" away from the joist because of the bracket.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Greetings and Happy 2021.

I used 4 - 8/32 screws to attach the light to the box because I have one time encountered a light that was so heavy it broke the screw holes sections of the fiber type nail up light box.

Thanks,

The chandelier weighs exactly 50 lbs? With or without bulbs?
If I had already encountered one that already broke those old brown boxes I wouldn’t have tried it again..

I can’t tell you how many I’ve been in those brown or blue plastic boxes that have Sheetrock screws ran in them because someone lost the screws that came with the kits.
 

Rock86

Senior Member
Location
new york
Occupation
Electrical Engineer / Electrician
I can’t tell you how many I’ve been in those brown or blue plastic boxes that have Sheetrock screws ran in them because someone lost the screws that came with the kits.
You mean the spare parts bag? Meh... who needs those. :LOL:
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Would you please give a description if this side-mount retro box kit?
The first pic is weird because it shows the box upside-down. You separate the bracket from the box, mount it to the joist through the ceiling hole, put the wire in a KO, and mount the box back onto the bracket.

1611360524004.png 1611360544068.png 1611360555935.png

 

kwired

Electron manager
Location
NE Nebraska
you puta 50lb. fixture on a plastic fiber box? I thought they were only rated by NEC for like 6 or 10 lbs.
You might be thinking of device boxes supporting luminaires having that restriction and/or retrofit type boxes that only held in place by clamping to the drywall or other finish.
 
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