Cuprothal is an austenitic copper-nickel alloy (CuNi alloy) with low resistivity. It is used for the negative leg of the following types of thermocouples and compensating cables: E, J, T and KCB (VX). Cuprothal can be used at temperatures down to 20 K where its Seebeck coefficient is about 8 µV / K.

Thermocouple type E has the highest emf output of any common thermocouple and is for this reason used in thermal generators (thermopiles).

Cuprothal type T is matched with elecrolytic copper (ASTM standard B3). Thermocouple type T is both used in laboratory and industrial applications.

Cuprothal type KNCB (VNX) is matched with electrolytic copper when used in compensating cables for thermocouples type K.