Thermocouple extension wire is a flexible, insulated wire used to extend a thermocouple signal from a probe back to the instrument reading the signal. It works accurately over a narrower temperature range than thermocouple wire and can't be used in the sensing point (or probe part) of the thermocouple. It is typically used as an extension to a measuring instrument over long distances.Thermocouple wire and cable are types of flexible, insulated wire that sense the temperature of an object and feed that information to a temperature control device or to a temperature measuring or monitoring device. They can also be used to create the sensing point (or probe) in a thermocouple. They are commonly used to maintain or monitor a component's temperature in industrial processes where high heat is present, such as kilns, gas turbine exhaust, or diesel engines. They are also used in safety devices, such as flame sensors in gas-powered appliances.