An electrical-connection device, particularly for photovoltaic-cell panels, has: a first electrical terminal, designed to be connected to apparatuses for generation or use of electrical energy and to extend in a fixed position through a wall for support of the connection device; a seal for fluid-tight coupling of the first electrical terminal to the supporting wall; a second electrical terminal connected to the first electrical terminal and to an electrical wiring external to the supporting wall; and an electrically insulated liquid-tight chamber, housing at least partially the first electrical terminal and the second electrical terminal.