[RE-wrenches] 90 degree wire bends

[Ray Walters]

Was that on the hots or neutral? It's possible that might have been 
lightning too. I've heard of lightning using the pump wiring to get to 
the very well grounded well water.

Ray

On 11/18/2011 1:47 PM, Nik Ponzio wrote:
>  I had an off-grid customer report that their huge well pump surge 
> caused an insulation melt-down at a tight bend in the wire.
>
>
> On Wed, Nov 16, 2011 at 11:01 PM, Darryl Thayer <daryl_solar at yahoo.com 
> <mailto:daryl_solar at yahoo.com>> 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 <mailto:ray at solarray.com>>
>     *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org
>     <mailto: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
>>
>>
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