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Bend Radius #176303
03/28/08 11:39 PM
03/28/08 11:39 PM
Admin  Offline
Joined: Oct 2000
Posts: 3,495
How come Square D can violate the minimum bending radius rules and we can't?

Is there some exemption for manufacturers? I must admit, it's a pretty bend, probably done on some hydraulically operated jig at the factory.

Linda Evans

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Re: Bend Radius [Re: Admin] #176372
03/30/08 03:36 PM
03/30/08 03:36 PM
BigJohn  Offline
Joined: Mar 2004
Posts: 391
Boston, MA
What is this equipment? No phase identification either?

Last time I saw bends even remotely close to those, the tool that had made them had also destroyed the insulation. I wouldn't be too happy to open a cabinet and find that.


Re: Bend Radius [Re: BigJohn] #176374
03/30/08 06:08 PM
03/30/08 06:08 PM
InspectorE  Offline
Joined: Oct 2004
Posts: 51
Hudson WI USA
Sorry about not giving more info. This is a Square D service entrance box (meter on left half) with 2 - 200 amp main circuit breakers in the right half. This is how it came from Square D. That's why I question why Square D can do this with a listed item. The insulation isn't broken on any of the 90 degree bends, I looked very carefully.

Re: Bend Radius [Re: InspectorE] #176389
03/30/08 11:35 PM
03/30/08 11:35 PM
Lostazhell  Offline
Joined: Feb 2004
Posts: 1,431
Bakersfield, CA (Originally Or...
It's not just Square D... I've seen the same in Cutler Hammer, Siemens, Allen Bradley, Furnas panels and MCC's out where I work..... UL governs safety of equipment, NEC governs safety of it's installation

Re: Bend Radius [Re: Lostazhell] #176392
03/31/08 08:54 AM
03/31/08 08:54 AM
ghost307  Offline
Joined: May 2005
Posts: 934
Chicago Illinois USA
This looks like single conductor building wire with 600VAC insulation.

Which mimumum bending radius rules are they violating?

Re: Bend Radius [Re: ghost307] #176477
04/03/08 06:32 AM
04/03/08 06:32 AM
SteveFehr  Offline
Joined: Mar 2005
Posts: 1,213
Chesapeake, VA
They can do this because they test it like that, and it passes. They can do a lot of other things that are illegal per NEC, too, for the same reason- smaller conductors, for instance. NEC is rather conservative, as we all know.

So, don't look at it as exceeding the bend radius for cable, look at it as insulated cylindrical busbar!

Re: Bend Radius [Re: SteveFehr] #176478
04/03/08 07:09 AM
04/03/08 07:09 AM
IanR  Offline
Joined: Dec 2004
Posts: 328
Palm Bay FL USA
Well put, Steve.
Remember the NEC has to be a very conservative catch all for many unseen installation parameters, that may or may not happen. The manufactures of these panels can test these units under controlled conditions. Then they specify the conditions, that these panels are used under, by listing them that way.

Re: Bend Radius [Re: IanR] #176482
04/03/08 09:20 AM
04/03/08 09:20 AM
InspectorE  Offline
Joined: Oct 2004
Posts: 51
Hudson WI USA
"insulated cylindrical busbar"

I like that definition, maybe 2011 NEC will have it. Reminds me of the euphemism we used in the Army "aggressive retrograde maneuver" for run like hell.

Big difference between NEC and UL listing, ditto what the power company can do on their side of the meter.

Thanks folks!

Re: Bend Radius [Re: InspectorE] #176503
04/04/08 10:25 AM
04/04/08 10:25 AM
Zapped  Offline
Joined: Oct 2002
Posts: 482
Huntington Beach, CA, USA
This is the norm for the internal wiring in meter/load-center pedestals. I have never encountered a problem resulting from this type of installation.

Re: Bend Radius [Re: ghost307] #176723
04/10/08 12:00 AM
04/10/08 12:00 AM
Nick  Offline
Joined: Aug 2001
Posts: 599
Riverside, CA
Originally Posted by ghost307
This looks like single conductor building wire with 600VAC insulation.

Which mimumum bending radius rules are they violating?

I am with ghost. For under 600V what section is being violated??


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