Abstract: Electric power socket (10) having structure (12) supporting electric contacts (20, 22, 24). A plug receptacle (18) having openings (100, 90) (102, 92) and (104, 94) therethrough is positioned for rotation in front of the contacts (20, 22, 24). The plug receptacle (18) is normally locked at an inactive position, at which it covers the contacts (20,22 24), by means of resiliently depressable locking tongues (142) which engage openings (90,94) of the plug receptacle. When pins of an electric plug are pressed into the plug receptacle (18) to pass through the openings (104,94) and (100,90) the pins engage the tongues (142), depressing them to allow the plug and plug receptacle to be rotated to align the plug pins with the contacts (20,22,24). Subsequent inward movement of the plug engages the pins with the contacts (20,22,24).