This standard applies to bayonet lampholders B15d and B22d for connection of lamps and semi-luminaires to a supply voltage of 250 V. It also covers lampholders which are integral with a luminaire or intended to be built into appliances. It covers the requirements for the lampholder only. For all other requirements, such as protection against electric shock in the area of the terminals, the requirements of the relevant appliance standard shall be observed and tested after building into the appropriate equipment, when that equipment is tested according to its own standard. Lampholders for use by luminaire manufacturers only are not for retail sale. The Subcommittee responsible for this standard is UK 521.2 "Lampensockel und -fassungen" ("Lamp caps and holders") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.