How do I extend a thermocouple wire?
Many measurement errors are caused by unintentional thermocouple junctions. Any junction of two different metals will cause a thermocouple junction. If you need to increase the length of the leads of your thermocouple, you must use the correct type of thermocouple extension wire (e.g. type K for type K thermocouples). Using any other type of wire will introduce a thermocouple junction. Any connectors used must be made of the correct thermocouple material and correct polarity must be observed.
Special grade thermocouple extension wire and connectors are available. Omega has thermocouple connectors (SMPW-X-M) for specific TC types available that will mate with the Data Translation MEASURpoint and TEMPpoint instruments.
Here are some links for more information about thermocouple wires: