ROSSLYN, Va. - The National Electrical Manufacturers Association (NEMA) has revised its standard DC 3-2003, "Residential Controls-Electrical Wall-Mounted Room Thermostats." At the same time, the trade association's Residential Controls Section has reaffirmed for continued use DC 10-1983 (R1989, R2003), "Residential Controls-Temperature Limit Controls for Electric Baseboard Heaters," and DC 20-1992 (R2003), "Residential Controls-Class 2 Transformers."
DC 3-2003 covers self-contained, electrical and electronic, wall-mounted room thermostats for heating and cooling. It provides specifications on ratings and classification, construction requirements, and testing and performance requirements, including the equipment necessary to test thermostat operation and performance.