<p>A socket part (1) has a receiving channel (3) for receiving the plug part (2) in which a protective device (4) is displaceably mounted in the receiving channel (3). The protective device (4) comprises a protective cover (5) which can be axially moved from a closed position to an open position and which is biased into the closed position by a helical compression spring (7). The protective device (4) further comprises an outer guide sleeve (6) which is slidingly joined to the protective cover (5) in such a way that these parts (5, 6) are telescopically extendable.</p>
