On Fri, 17 Apr 2009 22:54:38 GMT, Howard Eisenhauer
:>Some insulated multistrnd copper wire is pre-tinned and a lot is
:>What is the purpose of pre-tinned wire? As far as I can see the
:>advantage is that the copper core doesn't oxidise which means the
:>wire can be soldered or fixed to a terminate with only minimal
:>Sounds like a good thing to me, so why isn't almost all wire pre-
:>Is cost really so different?
:>Does the tinning-coating replace where copper would have been in
:>the overall wire and tinning is of higher reistence?
:>Is flexibility affected?
:In the telecom industry the rule is "silver on silver". Back in the
:bad old days there could be problems with diss-simmilar metals
:corroding & creating noise on circuits both from rectification effects
:& from current punch-through across the junction when voltage was
:applied to the circuit, i.e. "going off-hook". In some cases
:"sealing" current was (& still is) applied on a constant basis to
:circuits that didn't require it for operation, just to keep junction
:corrosion from getting bothersome.
:Although not part of the original Bellcore standard I've actually
:speced tinned wire for T1 circuits going into areas I knew were going
:going to be climate controlled.
That is correct. A typical manufacturer of internal switchboard cable
application chart shows that their Switchboard 100 product (equivalent to what
most western countries would use for internal cabling) is suitable for T1 and