Abstract: A retainer prevents the accidental separation of mating plug and socket connectors on electrical cords, or protects the connectors from inadvertent unsafe use. The retainer includes a housing which is open at one end and has a slit running along its length. An electrical cord is inserted into the slit, and the housing is moved along the cord so that the connectors enter the housing through the open end. The slit can be spiral and/or helical to reduce the possibility of the cord inadvertently coming free. A cover also having such a slit is placed on the other electrical cord and moved toward the open end of the housing. Interfitting structures removably secure the cover to the housing, thereby preventing separation of the plug and socket connectors. The interfitting structures can be arranged to engage at any point along a length span.