Diagnosing loose lamp holders / lamp sockets
Channel: inklipMedia / Robert Monk
Date: 25/04/2012

See more at:
http://www.phillylicensedelectrician.com/consequences-of-over-lamping/

Lampholders aka lamp sockets (edison base) may become loose in several ways. The entire socket may loosten from its mount to the fixture, making proper installation of lamps difficult or impossible without twisting and straining lead wires terminated at the base of the socket. The socket may have come loose from its mounting bracket, which may not cause any electrical difficulty until the screw drops out completely. Finally, rivets connecting the screw shell contacts to the insulating surround (usually white porcelain or white or brown plastic) may become loose due to age and/or overheating from excessive lamp wattage, resulting in intermittent flicker; or the spring tab forming the 'hot' (phase) contact at the base of the socket may be fatigued or broken, with similar results.