A 40 kA Nb3Sn conductor, designed to operate with forced helium flow at 4.5 K was tested in the SULTAN III facility, (I(max) = 50kA, B(max) (background) = 11T). The test sample and the operating conditions of the test facility are described. Two measurement procedures were used to investigate the conductor behaviour near the critical value : Sample current or temperature are increased up to the quench with background field and temperature or current reciprocally kept at steady state. The critical current of the conductor could be measured with the same criterion as for the basic strand (0.1muV/cm). The obtained results are discussed and compared with the basic strand performances. In addition some results on the thermohydraulic behaviour of the CIC conductor are presented.