[RE-wrenches] 90 degree wire bends

[Larry Crutcher, Starlight Solar Power Systems]

BANG. 
500 megajoules running through a wire at the speed of light. The poor little wire is doing the best is can to transmit the power, creating a freight train of spiraling, magnetic fields along the way. A tight bend, creating high inductance, looks like a 8 foot thick concrete wall. BANG. This time as the energy explodes from the wire to find a path of lesser resistance. That about sums it up.

I love it when I see "lightning protection" installations with neatly formed wires following every turn and contour tightly. Bang.

Larry Crutcher
Starlight Solar Power Systems



On Nov 16, 2011, at 9:01 PM, Darryl Thayer wrote:

> I have seen the lightening damage at tight bends, but in my electrical career of 60+ years I have not seen any other
> problems. 
> Darryl  
> 
> From: Ray Walters <ray at solarray.com>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Sent: Wednesday, November 16, 2011 12:11 PM
> Subject: Re: [RE-wrenches] 90 degree wire bends
> 
> It seems that if the strands were stretched and therefore thinned, that that would increase resistance, some. I think more importantly, the insulation  bunchs up and cracks, and is definitely compromised.  Also with strain hardening of copper, I'm sure some strands could break internally with a tight enough bend. I've heard at least for bare ground wires that lightning will jump off to the case at tight bends, but I've never actually seen that. 
> Aside from all that, is there actually an increased impedance from a tight bend (like in plumbing)? I don't know.  
> I've had to stop more than one journeyman from violating 300.34. I just tell them the bends should look like the long sweeps in conduit relative to the diameter of the wire: also purdy.
> 
> Aloha,
> 
> Ray
> 
> On 11/16/2011 10:35 AM, Marco Mangelsdorf wrote:
>> 
>> Some electricians have great fun in making 90 degree wire bends to try and make their enclosure wiring look so purdy.
>>  
>> Given the importance of maintaining wiring radiuses, this can’t be a good idea, can it?  Is the issue greater resistance when the wire is bent at a straight 90 degrees (or more)?
>>  
>> Thanks,
>> marco
>>  
>> 
>> 
>> _______________________________________________
>> List sponsored by Home Power magazine
>> 
>> List Address: RE-wrenches at lists.re-wrenches.org
>> 
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>> 
>> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>> 
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>> 
>> Check out participant bios:
>> www.members.re-wrenches.org
>> 
> 
> _______________________________________________
> List sponsored by Home Power magazine
> 
> List Address: RE-wrenches at lists.re-wrenches.org
> 
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
> 
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
> 
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
> 
> Check out participant bios:
> www.members.re-wrenches.org
> 
> 
> 
> _______________________________________________
> List sponsored by Home Power magazine
> 
> List Address: RE-wrenches at lists.re-wrenches.org
> 
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
> 
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
> 
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
> 
> Check out participant bios:
> www.members.re-wrenches.org
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20111119/1e5188b8/attachment-0004.html>