A lamp holder, also called a bulb holder or socket, is the fitting into which an electric light bulb is inserted, providing both the mechanical support for the bulb and the electrical connection to it. Lamp holders are made in brass, ceramic, Bakelite and modern plastics, and may include a switch, a shade ring or a shade carrier.
Two main types are found on antique and vintage fittings in Britain. The bayonet cap, known as B22, uses two pins that lock into slots and has long been the British standard, while the Edison screw, in sizes such as E27 and the smaller E14, was more widely used in Europe and America and is common on Continental lamps. Early brass holders, often with key switches or push-through switches and maker's names, are attractive in their own right and add authenticity to a lamp. However, old lamp holders may have perished insulation or worn contacts, and metal holders must be properly earthed. When restoring antique lighting, a competent electrician will decide whether an original holder can be safely reused or should be replaced with a modern equivalent of matching appearance. The type of holder also determines which bulbs can be fitted.
