Thermocouple grade wire is wire that is used to make the sensing point (or probe part) of the thermocouple. Extension grade wire is only used to extend a thermocouple signal from a probe back to the instrument reading the signal. The extension grade wire typically will have a lower ambient temperature limit in which the wire may be used.
Type N Thermocouple (Nicrosil / Nisil)
The Type N shares the same accuracy and temperature limits as the Type K. The type N is slightly more expensive. The type N has better repeatability between 572F to 932F (300C to 500C) compared to the type K.
Type N Temperature Range
Maximum continuous operating temperature: up to 2,300F (1,260C)Type N Thermocouple Grade WireShort term use: 2,336F (1,280C)Thermocouple grade wire, -454 to 2300F (-270 to 1,260C)Extension wire, 32 to 392F (0 to 200C)
