On Sat, 2 Sep 2017 11:49:52 +0100, Davey
wrote:


I too have used copper wire to connect TC's, and not had a problem,
the cold junction was always in the instrument providing the
measurement incidentally. I would not used copper for a serious long
term measurement strategy though, hence my lack of experience with
this type of setup.

I do recollect having problems with damp connections on more
conventional connectors in a similar application that seemed to be
exacerbated by the use of aluminium bootlace ferrules, so the
reactivity is the item of concern. Anything else can be quantified and
rectified.


AB

Back when Ford built a brand new factory near Valencia for the new
Fiesta, I went out there to commission the paintshop bake ovens. The
electrical contractor had no idea about the importance of the correct
use of Thermocouple compensating cable, and the long runs were
connected randomly. The effect of this was that some zone burners were
running flat out, while others were idling, and there was a total lack
of control of oven temperature. Once this was sorted out, it worked
properly. Until then, it was chaos.

Not quite the same approach as no actual thermocouples are in use
anywhere in the system.

There may be problems with the PT100 signals though, any other
analogues would be swamped by the 4mA min.

As I said, I am expecting anomolies and thanks to digital displays
these will be all too obvious.

The only think I cannot factor in is the possibility of corrosion,
this will take weeks to appear, as I mentioned I have no experience of
terminating K type connectors with copper wire.

Regards

AB