Unistrut as a Raceway Part 2

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factoryrat

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Relating to the Thread ?Unistrut as a Raceway??.
If ?? rod is use to hang/suspend Unistrut from a ceiling and the hanger rods pass through the interior of the Unistrut, to suspend it, can the interior space of the strut still be used as a raceway? Would this be a NEC violation?
 
Interesting question. I see nothing in Article 384 that addresses this specifically. 384.30(A) requires external mounting straps for surface mount applications, but 384.30(B) lists no such specific for suspension mounting, though it does require "approved, appropriate methods designed for the purpose."

Perhaps, what I find most interesting is that the issue is addressed in 314.23 as it relates to boxes (not pertinant or enforceable in your situation, but an interesting subnote) "screws shall not be permitted to pass through the box unless exposed threads in the box are protected using approved means to avoid abrasion of the conductor insulation"


The bottom line for me is that I see nothing in code expressly prohibiting you from doing as you plan (aside from the term "appropriate methods" which could be used by the inspector to reject the install), but I would personally find a better way, as the possibility of wire abrasion across the exposed threads is very real. Perhaps a look at the manufacturers catalog would be in order, see what they have to offer for mounting purposes.
 
factoryrat said:
Relating to the Thread ?Unistrut as a Raceway??.
If ?? rod is use to hang/suspend Unistrut from a ceiling and the hanger rods pass through the interior of the Unistrut, to suspend it, can the interior space of the strut still be used as a raceway? Would this be a NEC violation?
Click to expand...


The rod does not go through the strut. A bracket is used the attach the rod to the strut. If the rod went into the strut you wouldn't be able to snap the cover on.
 
As was pointed out in the other thread by Ryan, the strut must be listed as a raceway (See 384.6) and as such, as pointed out by petersonra, check with the manufactures listing instructions for mounting instructions.

Chris
 
infinity said:
Here is a link to a good illustration of the Kindorf system:

http://www.tnb-canada.com/en/catalogues/online/industrial_MRO/pdf/c11/07_strutcat_e.pdfhttp://www.tnb-canada.com/en/catalogues/online/industrial_MRO/pdf/c11/07_strutcat_e.pdfhttp://www.tnb-canada.com/en/catalogues/online/industrial_MRO/pdf/c11/07_strutcat_e.pdf
Click to expand...

In the bottom illustration on page 57 of this document, they show a hanger rod passing completely through the strut raceway with a nut on the under side.
 
mdshunk said:
In the bottom illustration on page 57 of this document, they show a hanger rod passing completely through the strut raceway with a nut on the under side.
Click to expand...

If you look closely the strut is not being used as a raceway, it's only supporting the fixture. The fixture is fed from the piece of EMT in the end.
 
mdshunk said:
In the bottom illustration on page 57 of this document, they show a hanger rod passing completely through the strut raceway with a nut on the under side.
Click to expand...

Yes it does, however they are not using the strut as a raceway in that application.

They are using perforated strut and I don't believe perforated strut is listed as a raceway.

I would use the brackets.
 
This begs an obvious question for me....

Exactly how popular is strut as raceway anyhow? I don't use it as a contractor. I used it maybe twice as an employee. I make it a point to look around in the bar joists when I'm in building's that I didn't wire. I very seldom see strut as raceway.

Is this a geographical thing? As expensive as it must be, is there any cost advantage in terms of conduit labor saved to a merit shop?
 
Marc I have only worked with it once, it both supported and supplied HID lighting for indoor tennis courts.

For that application it was perfect, we would have needed strut to hang the fixtures anyway. The ballast hung on the bottom and the reflector / lamp assembly mounted on the top facing up toward the white ceiling.

All the lighting circuits ran inside the strut, it was a slick looking installation once the painters did their part.
 
iwire said:
Yes it does, however they are not using the strut as a raceway in that application.

They are using perforated strut and I don't believe perforated strut is listed as a raceway.

I would use the brackets.
Click to expand...


Perforated unistrut makes for a great place to tie wire for signs ,hangers all those things you really want in a raceway with energized wires !!!!!!
 
Marc,
I work in a large factory and our electricians have added many florescent lights. We have large open areas to light. We hang 20 foot threaded rods from the structural steel in the ceiling and let it hang straight down. We then hang our lights off the suspended unistrut. Many times it is convenient to use the unistrut as a raceway.

The strut we use is not perforated. We drilled 1/2" holes in the bottom of the strut so we could pass the threaded rods through the strut and screw on securing nuts.
 
I have used the unistrut raceway system in a few industrial applications and it is pretty nice once you get all the parts together.

We fed lighting as well as installed receptacles in it in some locations.

No hangers went through the raceway though.

Roger
 
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