Thermocouple assembly with a length of 48 IN™ designed as a universal replacement part for gas furnaces, boilers, and water heaters that utilize a thermocouple flame sensor constructed of nickel alloy and magnesium oxide insulation to provide an electrical signal to the gas valve to indicate the pilot light is lit and if the pilot light goes out, the thermocouple stops sending a signal to open the gas valve, shutting off the gas supply as a safety precaution.