PT100 sensors work with 4 wires. That means the length of the cable has no effect on the measure. Tests have been carried out up to 200 meters, and results are consistent.
In order to filter external electromagnetic disturbance which could cause bad measures, we advise to use a cable with a braid shiel. The common reference is LIYCY4*0.34mm².
The shiel of the original sensor cable must be connected to the shield of the extended cable.
Posted in: Wiring and probes