[PLUG-TALK] Cat5e cable: open [UPDATE]

Rich Shepard rshepard at appl-ecosys.com
Sun Dec 29 12:42:57 PST 2019


On Sun, 29 Dec 2019, Denis Heidtmann wrote:

> You might be able to get a good guess using capacitance. Assume one wire
> is broken. Verify with ohm meter. Now measure capacitance of the open wire
> from each end. Those values should sum to the capacitance between two good
> wires. The capacitance measurement needs to be at a low enough frequency
> to avoid induction complications.
>
> Apply a hf pulse to one end of the broken wire.  Ground the other wires.
> Pass a high impedance 'scope probe along the outside of the cable until the
> pulse drops off suddenly.

Denis,

Hadn't considered putting a multimeter across each wire's ends and measuring
the resistance. Of course these require cutting the plug off the other end
for perhaps little gain. I have a Fox & Hounds connectivity tester I've used
on phone wires to find the proper pairs and could use that.

> Another approach: apply a high voltage between the ends of the broken wire.
> Search for the spark.

And see where the wire cover melts?

Recycling is the parsimonious solution.

Regards,

Rich



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