Supporting octagon ceiling boxes.

Reply

  #1  
Old 01-15-17, 08:10 AM
Member
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 188
Received 0 Votes on 0 Posts
Supporting octagon ceiling boxes.

My barn has trusses 4' on center, with 2X4's running perpendicular on 4' centers, that create 4' squares. I'm going to install octagon boxes in the center of some of these squares, with lamp holders and LED light bubs. I'm using 1/2" EMT. MY question is, Can the EMT support those boxes on their own, or do I need to support the boxes as well? Thanks. John.
 
Sponsored Links
  #2  
Old 01-15-17, 08:28 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,973
Received 59 Votes on 52 Posts
Conduit can not be used to support boxes, they need to have their own support.

I would also not recommend using octagon boxes. I would use 4" x 4" boxes with square to round mud rings. Square boxes have more room and more knock outs available on each side.
 
  #3  
Old 01-15-17, 08:37 AM
Member
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 188
Received 0 Votes on 0 Posts
Can I use empty conduit as a support?
 
  #4  
Old 01-15-17, 10:04 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Location: USA
Posts: 4,069
Received 19 Votes on 19 Posts
If the conduit is supported independly of the box I guess you could,why not use a piece of Uni Strut ?
 
  #5  
Old 01-15-17, 11:05 AM
Member
Join Date: Mar 2010
Location: USA
Posts: 3,608
Received 24 Votes on 24 Posts
I would suggest a 2x2 horizontal wood member to span the 4' space and support the light fixture.

An alternative is a vertical chain or rod or similar support attached to the sheathing or ceiling above, provided that the fasteners can hold securely without going through roofing material on the other side of sheathing.

I do not think that an empty piece of 1/2" EMT mounted horizontally would adequately support a light fixture in the middle of a 4' span.
 
  #6  
Old 01-15-17, 11:23 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Why has no one suggested Unistrut? Isn't this what it is made for?

Name:  R0175974-01.jpg
Views: 67
Size:  25.3 KB
 
  #7  
Old 01-15-17, 02:27 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,973
Received 59 Votes on 52 Posts
Can I use empty conduit as a support?
I would say yes, and no, depending how you use it. If you just used the empty conduit connected to the box with an EMT connector, I would say no. If you layed the conduit horizontal across the back of the box and attached the box tot he conduit with some self tappers, or attached some conduit minis to the box with some 1/4 - 20 screws and nuts and then clamped it to the conduit, I would say that is OK. I would say use 3/4" conduit or larger, and of course, the conduit would need to be attached on both ends.

Why has no one suggested Unistrut? Isn't this what it is made for?
See post #4

Unistrut is great but at $17 a 10' stick it is an expensive way to go. 2x2's are cheap.
 
  #8  
Old 01-15-17, 02:32 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
I completely agree with Tolyn on all counts!
 
  #9  
Old 01-15-17, 06:43 PM
Member
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 188
Received 0 Votes on 0 Posts
Thanks guys for the help. I think I'm going to go with the 2X2's. The uni strut is nice, but the amount that I would need, is cost prohibitive. John.
 
  #10  
Old 01-16-17, 03:46 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 2 Votes on 2 Posts
2x2's spanning 4' are going to be borderline supportive in that they will tend to bow and warp. I would go ahead and install 2x4 lumber on edge fastened between the adjoining supports.
 
  #11  
Old 01-16-17, 06:28 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Location: USA
Posts: 4,069
Received 19 Votes on 19 Posts
Ray check post #4,great product although a bit expensive.
Geo
 
  #12  
Old 01-16-17, 07:30 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Sorry Geo. skimmed the thread to fast and missed your post. I've been a fan of Unistrut ever since I built a roof rack for my van. Cost way less than a factory rack and so I tend to forget it is relatively expensive.

Here I wouldn't even consider 2x2 because all they sell is #1 or better at the same or greater than the cost per foot of stud grade 2x4s. If I want 2x2s I can just rip 2x4s and they cost half as much.
 
  #13  
Old 01-16-17, 11:35 AM
Member
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 188
Received 0 Votes on 0 Posts
An even better idea. 2x4's it is. Thanks guys.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: