Abstract: A power distribution unit includes a housing; a plurality of power outlet modules accommodated in the housing, at least one of the power outlet modules including a socket having at least three electrical terminals which are configured to connect with one power cord plug of various types of power cord plugs, including a C14 plug and a C20 plug, and a sliding cover having a central opening, the sliding cover being slidable on an outer casing of the socket and engageable with the power cord plug when the power cord plug is completely inserted into the socket, thereby providing a secure connection between the socket and the power cord plug; and at least one power input module providing power to the power outlet modules.