"240.83(D) [Marking] Circuit Breakers Used as Switches
A new sentence requires any circuit breaker used to switch HID lighting to be marked HID.
Two types of circuit breakers have been available for switching lighting – SWD and HID. The HID rated circuit breaker is listed to switch both fluorescent and HID. The SWD circuit breaker is only listed to switch fluorescent lighting.Many manufacturers will discontinue the SWD version and only offer the HID style. This requirement is only for circuit breakers used to switch lighting, but the HID could be used for HID (HPS, MV and Metal Halide) as it is heaver duty."
Apparently the new HID breakers are being produced to meet this new (2002) NEC requirement.
Ok, new requirement in that is now explicitly spelled out. Previously required under the general rule of using equipment per listing requirements. To have used a breaker to switch HID lighting prior to the 2002 code you had to use an HID breaker, but you had to know that these were the breakers listed for that use.