Thermocouples must have a direct termination to the temperature controller and not joined, unless the correct compensating cable is used. Carel Probe. Carel NTC probes are supplied in a plastic sheath with 6mm diameter, they are suitable for a variety of industrial applications. Designed to accompany a variety of Carel ; Tempatron controllers. 6 x 15mm IP67 plastic sheath 3m lead length