Re: Tinning wires - was Gecko burned out

There is another issue with using tinned wires
with screw terminals, clamp terminals, and
crimp connections. If you twist multiple strands
of wire together and tin them, the result is a
relatively rigid bundle. Even if it does not
cause issues with the connection, it will pose
a problem at the transition from the tinned
bundle to the individual stands. The cause
is flexing of the strands comes to an abrupt
stop where the bundle is tinned. A properly
designed crimp or clamp provides a tapered
entry to distribute the flexing so that the
individual strands are less likely to break.

If the strands are individually tinned and not
fused into a bundle this problem is avoided.

Regards,
Steve Stallings


--- In CAD_CAM_EDM_DRO@yahoogroups.com, Major A <mandras76@y...>
wrote:

>
> > It's a common sense issue. If we tin the strands into a solid
> > diameter then clamp the diameter between two flat surfaces the

area

> > of contact would be smaller than a bundle that can be flattened

when

> > clamped.
>
> Hmmm. I haven't wired my Xylotex up yet, but it's certainly going to
> be with tinned wires. Tin is soft enough so that the screw can

squash

> it almost like it does untinned wire. In fact, the surface area of

the

> contact is larger than without tin because the soft tin can fill in
> the gaps between the rigid copper contacts and wire strands. Also,

tin

> prevents corrosion: remove an untinned copper wire from its terminal
> after it has been in there for 10 years, and chances are it will be
> brittle from corrosion. You don't get anything like this with tinned
> wires.
>
> I had a colleague at work once who always clamped untinned wires. I
> made the same connections with tinned wire. Needless to say, his
> connections never worked properly, mine always did.
>
> Andras