[RE-wrenches] Factory Over bent Wiring

[Ray]

I think if we showed those pictures to a THHN wire manufacturer, they 
would not approve of deforming the insulation to that degree.  We are 
also talking about load centers with the same bending space available to 
the factory as we electricians have.

I also want to point out that Midnite has been very proactive with their 
wire bending techniques.  I posted a picture of their work as an example 
of 'how to do it'.  I'm now calling on other manufacturers to do the same.

Thanks,

Ray Walters
Remote Solar
303 505-8760

On 10/16/18 11:21 AM, bob at midnitesolar.com wrote:
>
>
> Ray is coming at this from an electricians viewpoint. He is correct if 
> talking about wiring outside of a UL or ETL listed product.
>
> The reason for wide radii in wiring is so the wires can be rerouted 
> and terminated a few times.
>
> 8 times the diameter is a very large bend radii and would never fly 
> inside a product, so why can a manufacturer do it?
>
> Copper has the tendency to work harden when bending back and forth. 
> That will damage the current carrying characteristics of a wire.
>
> Bending a wire once does not work harden them. The insulation can get 
> scrunched depending on the actual bend radii, but it is
>
> only cosmetic after one tight bend. There are no actual cracks that 
> would jeopardize the insulation integrity.
>
> We have investigated this and determined it to be cosmetic in nature 
> for a single bend. That said, I don’t like it either
>
> because it makes installers nervous and doesn’t look good. The tight 
> wire bends are no different from putting tight bends
>
> on a sheet metal copper busbar. We do this all the time and always 
> have. Testing shows that it does not constrict electrical flow.
>
> If you straighten that same copper busbar and bend it again, it is 
> likely to break in half. That is work hardening to the extreme.
> So, there is no violation from tight wire bending inside a listed box. 
> A listed box does not have the same restrictions as the NEC.
>
> Believe me, I too do not like zero radii bends and we have custom made 
> pliers that give the wire a gradual radii, but that is cosmetics only.
>
> The wire is not actually damaged unless you straighten it up and 
> re-bend it. We do not do that!
> Thanks,
> Robin Gudgel
> MidNite Solar
>
>
>
> On 10/15/2018 11:27 AM, Will White wrote:
>> NEC doesn't apply to the interior components of a UL listed device 
>> although I do see your point. I'm assuming they designed it taking 
>> that bend into consideration.
>>
>> On Mon, Oct 15, 2018 at 1:20 PM Ray <ray at solarray.com 
>> <mailto:ray at solarray.com>> wrote:
>>
>>     Greetings;
>>
>>     I've noticed several of the factory wired power panels over the
>>     years from Magnum, Outback, Midnite, Etc are not compliant with
>>     NEC 300.34 wire bending radius. (Radius should not be less than 8
>>     times the diameter) Basically they should look like sweep bends
>>     in PVC conduit, not plumbing.  Here's a pic from a recent Magnum
>>     system
>>
>>     You can see the kinks in the insulation on the inside of the
>>     bend, and the color fading on the outside from being
>>     overstretched.  Some might think this is neat work, but its
>>     actually permanent wire damage and a code violation.  Imagine the
>>     strain on the copper inside.
>>
>>     Midnite is very proactive and has improved, I ask that Magnum do
>>     the same and soon.
>>
>>     Thanks,
>>
>>     -- 
>>     Ray Walters
>>     Remote Solar
>>     303 505-8760
>>
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>> *Will White*
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