On Fri, 17 Apr 2009 22:54:38 GMT, Howard Eisenhauer
wrote:

:On Fri, 17 Apr 2009 04:14:40 +0100, Sandi wrote:
:
:Some insulated multistrnd copper wire is pre-tinned and a lot is
:not.
:
: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
:cleaning.
:
:Sounds like a good thing to me, so why isn't almost all wire pre-
:tinned?
:
: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.
:
:H.


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
DS1 applications.
http://www.superioressex.com/uploade...lect_chart.pdf