Supporting octagon ceiling boxes.
#1
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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.
#2
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.
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.
#5
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.
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.
#7
Can I use empty conduit as a support?
Why has no one suggested Unistrut? Isn't this what it is made for?

Unistrut is great but at $17 a 10' stick it is an expensive way to go. 2x2's are cheap.

#10
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.
#12
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.
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.