Hello Steve,

You have my sympathy. Getting the quantitative data you're
looking for seems near impossible.

To my understanding, admittedly subject to recalibration,
neither the USCG nor the ABYC standard requires tinned
copper conductors.

The ads often read "our tinned copper wire meets ABYC
standards" suggesting that tinning is part of the standard,
when the conformance reference is technically to stranding,
insulation, and color!

We know that tin oxidizes more slowly than copper, and that
the copper oxides that form when copper corrodes are
non-conductive.

Beyond that, all I can find are anecdotal and largely
unscientific reports, and the "tinned copper reduces
corrosion" mantra.

Good luck

Chuck

Steve wrote:
I realize that this might be a prompt for lots of argument but anyway....

I have just started rewiring the 12V side of my boat. While ripping out
the miles of cable that seemed to power big blobs of ancient insulating
tape I have noticed that the continued wire seems to have survived well.
i.e. the boat is 20 years old and the original stuff is which was mainly
continued is fine. I can see no signs of corrosion even after stripping
large lengths. The insulation is a different matter in some cases. It is
in a poor state, especially were it is exposed to heat or sun but that
is a different issue.

So the question is: Is tinned copper really necessary? It is more than
twice the price of pure copper and has the same insulation! I am
prepared for quotes from various recommendations and standards (many of
which I have read) but what I would really like is some real empirical
engineering info here. I have been involved in standards bodies and know
how they work. Good ideas can very easily become mandatory requirements
because it could be critical in some obscure cases. I was trained as an
engineer which is to say I can live with the concept of good enough for
purpose. If the life expectancy of pure copper is half that of tinned
and tinned will last 30+ years, I can live with having to change the
wire again in 15 years.

Steve