<P> Plastics are suitable insulators for low temperatures parts of a thermocouple, whereas ceramic insulation can be used up to around 1000 ° C. Other concerns (abrasion and chemical resistance) also affect the suitability of materials . </P> <P> When wire insulation disintegrates, it can result in an unintended electrical contact at a different location from the desired sensing point . If such a damaged thermocouple is used in the closed loop control of a thermostat or other temperature controller, this can lead to a runaway overheating event and possibly severe damage, as the false temperature reading will typically be lower than the sensing junction temperature . Failed insulation will also typically outgas, which can lead to process contamination . For parts of thermocouples used at very high temperatures or in contamination - sensitive applications, the only suitable insulation may be vacuum or inert gas; the mechanical rigidity of the thermocouple wires is used to keep them separated . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2014) (Learn how and when to remove this template message) </Td> </Tr>

The thermocouple circuit which is used to measure temperature works on