ceiling junction boxes
- Thread starter jemsvcs
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electricmanscott
Senior Member
- Location
- Boston, MA
Re: ceiling junction boxes
NEC 314.27 (A)
NEC 314.27 (A)
G
Guest
Guest
Re: ceiling junction boxes
My experience has been that round mud rings are usually intended for luminaries and usually come tapped for 8/32 screws.
My experience is that single-gang, double-gang, etc. mud rings are usually intended for receptacles & switches and usually come tapped for 6/32 screws.
There are round covers that are prepped to receive a single or duplex receptacle. The round cover typically hangs on the round mud ring. The receptacle typically bonds to the round cover with one center screw and one (or two) 6/32 through bolts.
Does 314.27 rule out using 6/32 boxes for luminaries? Conventionally I would use a round mud ring (or octagon box) and it would have 8/32 screws. I'll let somebody smarter than me chime in with an interpretation of 314.27.
My experience has been that round mud rings are usually intended for luminaries and usually come tapped for 8/32 screws.
My experience is that single-gang, double-gang, etc. mud rings are usually intended for receptacles & switches and usually come tapped for 6/32 screws.
There are round covers that are prepped to receive a single or duplex receptacle. The round cover typically hangs on the round mud ring. The receptacle typically bonds to the round cover with one center screw and one (or two) 6/32 through bolts.
Does 314.27 rule out using 6/32 boxes for luminaries? Conventionally I would use a round mud ring (or octagon box) and it would have 8/32 screws. I'll let somebody smarter than me chime in with an interpretation of 314.27.
Re: ceiling junction boxes
Jemsvcs, I have been told to do the same thing just like you.
Reason you are being told to use the 8-32's is to support the weight of a suspended ceiling fan. While you may or maynot be putting one in now you will be able to put one in at a future date up to 35 lbs.
There are listed boxes that are pemitted to support up to 70 lbs that we use in areas that definately will have a ceiling paddle fan/ light.
John
Jemsvcs, I have been told to do the same thing just like you.
Reason you are being told to use the 8-32's is to support the weight of a suspended ceiling fan. While you may or maynot be putting one in now you will be able to put one in at a future date up to 35 lbs.
There are listed boxes that are pemitted to support up to 70 lbs that we use in areas that definately will have a ceiling paddle fan/ light.
John
charlie
Senior Member
- Location
- Indianapolis
Re: ceiling junction boxes
From the NFPA NEC Handbook:
"Device boxes are designed for the mounting of snap switches, receptacles, and other devices, usually with 6-32 screws (No. 6 screws with 32 threads per inch). Generally, device boxes are not suitable for supporting other than lightweight wall-mounted luminaires. The exception to 314.27(A) permits luminaires such as wall-bracket types or sconces weighing less than 6 lb to be supported by a device box using No. 6 or larger screws. For heavier or ceiling-mounted lighting luminaires, see 410.16, Means of Support. The outlet box is required to provide ?adequate? support."
From the NFPA NEC Handbook:
"Device boxes are designed for the mounting of snap switches, receptacles, and other devices, usually with 6-32 screws (No. 6 screws with 32 threads per inch). Generally, device boxes are not suitable for supporting other than lightweight wall-mounted luminaires. The exception to 314.27(A) permits luminaires such as wall-bracket types or sconces weighing less than 6 lb to be supported by a device box using No. 6 or larger screws. For heavier or ceiling-mounted lighting luminaires, see 410.16, Means of Support. The outlet box is required to provide ?adequate? support."
IMO, Yes
pierre
Senior Member
- Location
- Westchester County, New York
Re: ceiling junction boxes
I spoke to Richard Loyd of CMP 3, and he had submitted the change for this requirement. He said the result of the section requirement was not quite what his original intention was when he submitted it, but sometimes this is the result. This requirement was not always in the code, I believe it was added only one or two cycles ago.
If you were to look in manufacturer's catelogs, you will see the boxes with the 6/32 screws are labeled 'device' boxes.
Pierre
I spoke to Richard Loyd of CMP 3, and he had submitted the change for this requirement. He said the result of the section requirement was not quite what his original intention was when he submitted it, but sometimes this is the result. This requirement was not always in the code, I believe it was added only one or two cycles ago.
If you were to look in manufacturer's catelogs, you will see the boxes with the 6/32 screws are labeled 'device' boxes.
Pierre
Re: ceiling junction boxes
Thanks for all your comments.
I was aware of the Exception to 314.27(A) for wall mounted luminaires weighing no more than 6 lbs., but 8/32 size screws are not mentioned specifically by the NEC.
It makes sense that 8/32s support more weight...I guess my confusion as to the support of fluorescent luminaires was because I was using toggle bolts through the wallboard anyway, so I didn't see that 8/32s or 6/32s at the outlet box were all that important. Then again...'future use' at the outlet could require the heavier screw.
If anyone has a reference to strength of 8/32s versus 6/32s, a link would be appreciated.
Thanks again!!!
Thanks for all your comments.
I was aware of the Exception to 314.27(A) for wall mounted luminaires weighing no more than 6 lbs., but 8/32 size screws are not mentioned specifically by the NEC.
It makes sense that 8/32s support more weight...I guess my confusion as to the support of fluorescent luminaires was because I was using toggle bolts through the wallboard anyway, so I didn't see that 8/32s or 6/32s at the outlet box were all that important. Then again...'future use' at the outlet could require the heavier screw.
If anyone has a reference to strength of 8/32s versus 6/32s, a link would be appreciated.
Thanks again!!!
G
Guest
Guest
Re: ceiling junction boxes
It's been a non-issue for me because I haven't encountered an octagon box or round mud ring that has 6-32 taps.
After re-reading the original question I am left to assume that jemsvcs has used non-round mud rings to hang luminaires.
Charlie, I'm with you on the Handbook read but 8-32 sure isn't spelled out in the NEC (that I can find). Pierre, righto about the mfg. specs:
It's been a non-issue for me because I haven't encountered an octagon box or round mud ring that has 6-32 taps.
After re-reading the original question I am left to assume that jemsvcs has used non-round mud rings to hang luminaires.
Charlie, I'm with you on the Handbook read but 8-32 sure isn't spelled out in the NEC (that I can find). Pierre, righto about the mfg. specs:
Here is the code citation from electricmanscott:
Question for jemsvcs: What kind of mud rings are you using that have 6-32 taps? What are you hanging on them? Wall or ceiling?
Re: ceiling junction boxes
Using bracketed 4x4x1 1/2 boxes mounted on ceiling joists...mud rings are square, however, i had been using device mud rings with rectangular openings as opposed to fixture mud rings with 8/32 round openings.
[ October 26, 2003, 05:40 PM: Message edited by: jemsvcs ]
Using bracketed 4x4x1 1/2 boxes mounted on ceiling joists...mud rings are square, however, i had been using device mud rings with rectangular openings as opposed to fixture mud rings with 8/32 round openings.
[ October 26, 2003, 05:40 PM: Message edited by: jemsvcs ]
G
Guest
Guest
Re: ceiling junction boxes
Like this? 4-square 2-gang 1/2-inch-raised plaster ring?
Like this? 4-square 2-gang 1/2-inch-raised plaster ring?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: ceiling junction boxes
I don't believe that if the outlet box is the not sole means for support as jemsvcs has said. The rings would not matter. and if someone were to install a different fixture it would be up to them to provide for the correct box/ring to mount it to as the NEC is not for future installs as the code can change by then and require something different by then. Wall mounted fixtures up to 6# can be installed to a box with 6-32 screws, but fluorescent luminaries don't normally mount to a box anyway as most just line up with the hole I haven't seen any with holes in them for screws to mount it to a box. so why would it be an issue to how much the box can support if the fixture will not be directly mounted to the box? and yes it still does have to have a EGC bond to the box. This could be in the form of a screw.
I don't believe that if the outlet box is the not sole means for support as jemsvcs has said. The rings would not matter. and if someone were to install a different fixture it would be up to them to provide for the correct box/ring to mount it to as the NEC is not for future installs as the code can change by then and require something different by then. Wall mounted fixtures up to 6# can be installed to a box with 6-32 screws, but fluorescent luminaries don't normally mount to a box anyway as most just line up with the hole I haven't seen any with holes in them for screws to mount it to a box. so why would it be an issue to how much the box can support if the fixture will not be directly mounted to the box? and yes it still does have to have a EGC bond to the box. This could be in the form of a screw.
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