A bus bar with three phase conductors and one neutral conductor is engageable by an adapter in the shape of an elongate plug designed to connect an external circuit across the neutral conductor and a selected phase conductor. The adapter housing contains two parallel shafts A, B each carrying a resilient...http://www.google.es/patents/US4211460?utm_source=gb-gplus-sharePatente US4211460 - Adapter for connecting a load to a bus bar
