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