Pair of irreversible complementary connectors

A pair of irreversible female and male connectors (2,1) fitting one in another have respectively female and male housings (22, 2), and the female housing (22) has a cavity (23) with a front opening so as to fit on the male housing (2) along an insertion direction. The female housing (22) has pin contacts (28) in placed the cavity and partitions (25) formed in it along the direction so as to separate the contacts (28) one from another. Socket contacts (42) engaging the pin contacts are placed in the male housing (2) that has cutouts (6) fitting on the partitions (25), and each partition having opposite sides (35,36) asymmetrical about a cross section center of the partition. Each cutout (6) also has asymmetrical sides (45,46) corresponding to the sides of each partition, such that the connectors are inhibited from engaging one another if one of them is reversed upside down, so that the pair of connectors are unlikely to come into wrong and upside-down connection, thus ensuring a stable and reliable mutual engagement even if they are designed thinner and smaller in size as required for the high-voltage type connectors.