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#176303 03/28/08 11:39 PM
Joined: Oct 2000
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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]

Admin #176372 03/30/08 03:36 PM
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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

BigJohn #176374 03/30/08 06:08 PM
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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.

InspectorE #176389 03/30/08 11:35 PM
Joined: Feb 2004
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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

Lostazhell #176392 03/31/08 08:54 AM
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This looks like single conductor building wire with 600VAC insulation.

Which mimumum bending radius rules are they violating?


Ghost307
ghost307 #176477 04/03/08 06:32 AM
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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!

SteveFehr #176478 04/03/08 07:09 AM
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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.

IanR #176482 04/03/08 09:20 AM
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"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!

InspectorE #176503 04/04/08 10:25 AM
Joined: Oct 2002
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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.

ghost307 #176723 04/10/08 12:00 AM
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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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