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#201465 - 06/02/11 02:01 PM Support of 4 inch square boxes
SJT Offline

Registered: 07/24/02
Posts: 242
Would it be allowed to support a 4 inch square (1900) box with threaded rod? The box contains a single receptacle, (110v)
The threaded rod is approx. 10' long, suspened from the steel work above. The box does sway (move) with the rest of the conduit when disturbed.
In the NEC, they talk about the box shall be securely fastened. Does that mean, no movement at all?
Then the job would need extra bracing. There are approx. 20 boxes. There is 3/4" rigid conduit installed between boxes.
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#201468 - 06/02/11 03:45 PM Re: Support of 4 inch square boxes [Re: SJT]
sparkyinak Offline

Registered: 07/08/07
Posts: 1288
Loc: Alaska
Since it is only rigid conduit, you will have to supply some sort of lateral support to prevent swaying. We may need additional info on what your intent is
"Live Awesome!" - Kevin Carosa

#201469 - 06/02/11 04:16 PM Re: Support of 4 inch square boxes [Re: SJT]
wire_twister Offline

Registered: 07/25/07
Posts: 265
Loc: Georgia USA
You can sleeve the threaded rod with 1/2 emt pipe, tightened up between the top and bottom jamb nuts and it will stiffen it considerably

Life is tough, Life is tougher when you are stupid

#201470 - 06/02/11 05:56 PM Re: Support of 4 inch square boxes [Re: SJT]
HotLine1 Online   content


Registered: 04/03/02
Posts: 6792
Loc: Brick, NJ USA
Some additional info:

Is the 3/4 RGC supported? What is the RGC length between boxes?

Are the 20+/- boxes in a straight row? Or what layout?

#201475 - 06/03/11 04:16 PM Re: Support of 4 inch square boxes [Re: SJT]
Tesla Offline

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
ERICO makes a series of appropriate box supports...

Check them out.


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