Abstract: A system for primarily supplying fishing boats lying berthed in harbor with electrical power, comprises a plurality of terminal boxes (1) which are countersunk along the edge of the quay and each contains electric power socket outlets (2), a drain hole (10) and a heating cable (19). The coverplate (5) of each box is self-closing, self-locking and lies on ground level, leaving in closed position an opening to the interior of the terminal box to permit passing therethrough a line (16) connectible to the electric power socket outlet and extending from an electrical connection box (18) which can be mounted on a boat (17) and has several electric power socket outlets and an electricity meter. In addition to electric power socket outlets, outlets for water, telephone service, compressed air, vacuum and/or fuel can be mounted in the boxes which can also be placed in airports and on camping sites.