Date:         Mon, 7 May 2012 04:44:49 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Engine Bay Negative Strap Questions. 1988 Westy. PICS.
Comments: To: neil n <musomuso@GMAIL.COM>
In-Reply-To:  <CAB2RwfhqXm+b1A70scXdvz5Xz_9+E_EopKj+r=gXnEOhJ5sLPg@mail.g
              mail.com>
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At 11:38 PM 5/6/2012, neil n wrote:
>https://picasaweb.google.com/musomuso/New1988Westy#5739625339124636370
>
>That corroded strap doesn't appear to be OEM and I can't see it
>anywhere it Bentley.
>
>Is this strap stock? If not, any harm in have it there? (engine
>management sensitive to the added negative to frame wire?)

It is stock.  I think the one you have is a home-made replacement as
it looks skinnier than the original and also looks as though it may
be tinned (original is bare copper).  It's braided for one of two
reasons: to provide a good radio-frequency ground* or for mechanical
resistance to vibrations, or possibly both.

*there's a phenomenon called "skin effect" which causes AC currents
to preferentially flow on the outside of conductors.  This effect
increases with frequency to the point that radio amateurs working up
in VHF bands often use silver-plated copper plumbing as wiring in
transmitters.  The braid has a great deal more surface area than an
equivalent volume of solid or stranded wire.  There's a fancier
version of this called Litz wire where every tiny strand is insulated
(bugger to solder to) but this is plain (flattened) hollow braid.


>I replaced it with a chunk of #12 wire.  (and thinking now maybe a
>stranded wire wouldn't wear well in this application)

It will be inferior for either of the reasons I stated.  A place that
installs transmitters for taxicabs and such ought to be able to help
you out.  Or a local ham operator, possibly of the less modern sort.

Yours,
David