[TowerTalk] Crimped Electrical Connections

[Lux, Jim]

On 11/17/21 8:05 AM, Paul Christensen wrote:
> I'm looking for input from others concerning best practices for crimping
> lugs onto solid copper wire that's exposed to the outside elements.   Here's
> why:
>
>   
>
> A few months ago, N4CC and I lost rotational control on one of our prop
> pitch rotators.  Our rotators are wired with #10 AWG copper Romex.  At the
> rotator, high-quality T&B copper ring lugs are crimped on the ends of the
> Romex.  A high-compression crimper is used on all connections.  Those
> connections are absolutely solid.
>
>   
>
> After installing a new section of Romex, we removed the old section, took it
> back to the shop and started looking for breaks.  None found.  Finally, I
> measured resistance between the lug's ring and the dug the other probe into
> the wire.  It still measured an infinite open.  That means all conductivity
> was lost between the lug barrel and the #10 wire.  All three lugs measure
> this way.   The lugs were crimped about six years ago and have been exposed
> to the weather.  Still, I didn't expect a well-crimped copper lug to lose
> all conduction properties.  The copper wire shows signs of black copper
> oxide which I believe is non-conductive.  And apart from creating a
> weather-proof box for the rotator connections, I'm looking for a long-term
> solution.  Frankly, I'm not keen about installing a small enclosure at the
> tower's top to protect the crimp, although it would certainly slow the rate
> of oxidation.  So that brings me to best practices.  Some possibilities:
>
>   

You didn't say if your AWG 10 Romex was stranded or solid.  If solid, 
were the lugs and the crimp dies designed for solid wire? Most commonly 
available crimp lugs are designed for stranded wire.

For instance T&B CTL "copper one hole lugs, short barrel" are for "AWG 
stranded, flexible cable, welding cable, and portable cord."  You have 
to hunt way down to find something designed for solid conductors.

http://tnblnx3.tnb.com/emAlbum/albums//StrategicPlatformCatalogs2013/CAT3_Blackburn_Comp_bookmarked.pdf