Why 10% though? (I like the mechanical integrity/vibration/heating angle)

Bob

On Fri, Sep 11, 2015 at 2:10 PM, Giamis, Andy <[log in to unmask]>
wrote:

> As my children say:
> 'Why?  Because I'm Batman"
>
> Electrical capacity, ampacity, would certainly be one factor.  Mechanical
> integrity would be another.  Just from vibration or flexure, 10% damage
> into any wire, solid or stranded, would certainly shorten the reliability
> versus a perfectly good cable.
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Wettermann
> Sent: Friday, September 11, 2015 1:16 PM
> To: [log in to unmask]
> Subject: [TN] Why Dad Why? Ampacity Degradation Reasoning in A610/20
>
> Dear Technetters:
>
> Had the following question from a client today...
>
> *...... a question regarding damaged conductors  (nicks and scrapes >10%).
> *
>
>
>
> *I have a 7 stranded wire that is cut and stripped by an outside supplier
> that has multiple wires coming in either nicked or scraped >10% resulting
> in a defect condition. My question is what is the reasoning or
> justification behind this accept/reject criteria?*
>
>
>
> * I can guess that it may have some limitations regarding current carrying
> capabilities or are subject to latent defects ( severed ) conditions due to
> the end use environment/vibration, corrosive etc.. *
>
> *My answer has to do this is:*
> The ampacity for the  conductor is a function of the material (copper or
> aluminum for example) and is based on its physical and electrical
> properties of the material. It is the current which can be carried such
> that the material would not up and be destroyed. The absolute value of this
> is a function of the amount of material (a nicked conductor would have less
> ampacity) and the reasons that the maximum deterioration was chosen to be
> 10% was <????>
>
> Maybe this iso ne of those times, just like you tell your children, just
> because!
>
> Bob Wettermann
> BEST Inc
>
>
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-- 
Bob Wettermann
BEST Inc
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Cell: 847-767-5745


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