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Posted By: Admin Bend Radius - 03/29/08 03:39 AM
Quote
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

[Linked Image from electricalphotos.com]
Posted By: BigJohn Re: Bend Radius - 03/30/08 07:36 PM
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.

-John
Posted By: InspectorE Re: Bend Radius - 03/30/08 10:08 PM
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.
Posted By: Lostazhell Re: Bend Radius - 03/31/08 03:35 AM
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
Posted By: ghost307 Re: Bend Radius - 03/31/08 12:54 PM
This looks like single conductor building wire with 600VAC insulation.

Which mimumum bending radius rules are they violating?
Posted By: SteveFehr Re: Bend Radius - 04/03/08 10:32 AM
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!
Posted By: IanR Re: Bend Radius - 04/03/08 11:09 AM
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.
Posted By: InspectorE Re: Bend Radius - 04/03/08 01:20 PM
"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!
Posted By: Zapped Re: Bend Radius - 04/04/08 02:25 PM
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.
Posted By: Nick Re: Bend Radius - 04/10/08 04:00 AM
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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