... & voltage 300V 4. Use only as Refrigerator Defrost Heater Wire. UL 3222 resistance wire Style 3222Insulated Wire Rating150 deg C, 300 Vac ... average, 40 mils minimum at any point. StandardAppliance Wiring Material UL 758. MarkingGeneral. UseFor use only as Refrigerator Defrost Heater Wire ... , blue, red, black, brown, yellow, green, transparent, yellow/green, etc UL 3222 resistance wire