Your response referencing the definitions of both "device" and "utilization equipment" made me think I should look at those more closely at those definitions.
"Device. A unit of an electrical system, other than a conductor, that carries or controls electric energy as its principal function"
Handbook commentary for Device - "Switches, circuit breakers, fuseholder, receptacles, attachment plugs, and lampholders that distribute or control but do not consume electrical energy are considered devices. Devises that consume incidental amounts of electrical energy in the performance of carrying or controlling electricity - such as a switch with an internal pilot light, a GFCI receptacle, or a magnetic contactor - are also considered devices. Although conductors are units of the electrical system, they are not devices."
"Utilization Equipment. Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting or similar purposes."
After looking at these two definitions more closely and especially the Handbook's commentary stating "...that distribute or control but DO NOT CONSUME ELECTRICAL ENERGY..." I no longer feel that a heater by itself would be considered a device and in turn would not require AFCI protection. However, here's the rub...I would however consider a wall mounted thermostat utilizing 120V to be a device and WOULD require AFCI protection, would it not?
