**** Professional wiring standards flame shields up ****

A truly horrible method which, none-the-less seems to work, when
terminating wires in terminal blocks is as follows. I almost blush to
promulgate this as I'm SURE that all the experts will explain why you
shouldn't do it, but  judge for yourself whether it is useful.

At one stage I did some work on taxi computers installed in cars.
These were wired in with screw down terminal blocks (no rising clamps
here!). There were 100+ computers involved and they were about 4+
years old so they represented a reasonable sample. Some person
unknown had used the following method to terminate the wires on SOME
of the computers. These "seemed" to have a lower incidence of broken
wires over a period for several years while I was involved with them.
I didn't, unfortunately, do a methodical tally on faults versus
termination method but was convinced enough that, in due course, I
adopted the method on all computers in this system that I dealt with.

i    Strip wire as usual. Tin or not etc as desired.

            XXXXX-----------

ii    Double the stripped end of the wire over onto the insulated
portion.
    (or the bare wire could be longer and wound around the insulated
end in a short spiral.
                      ___                                 _
               XXXXXI         or         XXXXX\\\\\XI

iii    Clamp with screw or clamp onto combined insulation and wire.
                          |
                       _\/_
               XXXXXI

I have discussed this method with a competent experienced friend and
we concluded that

i     It couldn't improve things.
ii    Various reasons why it would work if in fact it was found that
it did :-)

The method has its limitations.
The wire end should be under the screw/clamp or 180 degrees around
from it.
The insulation is cratered by the screw end.
Wiring inspectors and competent friends will look askance at you.
...................



**** Professional wiring standards flame shields still up :-)  ****

-----Original Message-----
From: Morgan Olsson <mrt@INAME.COM>

At 01:33 1998-11-22 +0000, Mark Moss wrote:
-snip-
>  The flux helps draw the molten solder down inside the
>insulation, achieving the same result.  You should probably use a
flux
>that won't tend to cause corrosion.
>
>BTW, when a Pace came to my company to give solder classes, he told
the
>students not to do this.  The reason was that, although the wire is
more
>likely to break, at least it breaks outside the insulation where
trouble
>shooting is easier.  My belief is that it's best not to have the
wire
>break in the first place.

\ Yes, but in my experience cables break much *less* when they are
tinned by
\ this method up a mm or two inside the insulation.
 \Because the insulation makes the bend much smoother.
\ That is, for small movements like vibration etc.\
\
\ For large wire movements like when the wire is pulled around making
sharp
\ bends directly at the solder joint then instead the tinned stiff
wire will
\ break earlier than an untinned flexible multistrand joint.  But of
course i
\ always clamp such cables!
\
 \As always, adjust your methods to the application       :)
\
\ Morgan