The National Electrical Manufacturers Association (NEMA) has published DC 3, “Residential Controls: Electrical Wall-Mounted Room Thermostats,” which was developed by NEMA’s Residential Controls Section.

Last published in 2003, the revised standard covers self-contained,
electrical and electronic, wall-mounted room thermostats for heating
and/or cooling. It also provides specs on rating and classification,
construction requirements, and testing and performance
requirements—including the equipment necessary to test thermostat
operation and performance.

DC 3 was extensively revised to reflect changing technologies in
heating and cooling systems, says NEMA, and the increasing use of
electronic controls. The standard also features a revised marking
section and updates to the test chamber specification.

“Thermostats are the key control component in heating and cooling
systems, and the point of interface for users,” said Dan O’Donnell,
chair of the 3DC subcommittee for thermostats. “DC 3 provides
specifications for the classification, testing, and performance of
thermostats to ensure safe and reliable operation. These extensive
revisions will prove very useful to the construction, property
management and utilities industries.”

CLICK HERE to download the standard (at no charge) or to buy the hard copy.