A power mains distribution panel including a data signal coupler providing a data path across multiple circuits therein. The power mains distribution or breaker panel provides mains power distribution from multiple non-neutral (i.e. having a voltage and providing a flow of current relative to each other or a common or neutral wire or virtual point, also called ‘hot’) mains circuits of a single or multiple phase for distribution within the distribution or breaker panel to branch circuits which in turn have a data path therebetween according to the present invention. Also described is a particular data signal coupler which may be used in the embodiments of the power mains distribution panels according to the present invention.