Abstract: Electrical connection apparatus is disclosed for achieving versatile connections between bus boards and electrical devices having conductive pins which extend through holes in the boards. Connections are achieved through transversely expansible conductive washers within the holes around the pins. Transverse expansion is caused by compression of individual washers along central axes of the holes, the compression being produced by expander means associated with the washers. Two expansible washer configurations are disclosed, one comprising spring material preformed with protuberances which are flattened to cause transverse expansion, and the other comprising a conductive elastomeric material.