Multi-pair extension cables are available for thermocouple calibration types E, J, K, N & T. Each conductor is covered with a polyvinyl chloride (PVC) jacket having a nominal thickness of 0.015 inch. Pairs are individually twisted to reduce magnetic interference. The twisted pairs are cabled and then shielded with a 0.0015 inch think aluminum-backed mylar tape and a #20 gage stranded copper drain wire to further minimize electromagnetic interference. The cable is then covered with an outer layer of PVC about 0.045 inch thick. A heavy, easy-strip nylon thread is included. Each cable also contains a polyvinyl-clad #20 gage copper wire for use as a signal connection. Cables are color coded on the individual conductors and overall. The individual pairs are marked for easy identification.