The present disclosure relates to a method of initializing a set of controllable units in an electrical system. The method comprises: A) obtaining, by a controllable unit controller module in a sequence of the controllable units, a discovery message on a non-addressable data pathway; B) broadcasting on an addressable data bus, by the controllable unit controller module, an identity of the functional unit; C) transmitting the discovery message to another controllable unit controller module in the sequence of the controllable units by way of the non-addressable data pathway; and D) recording, by the system controller module, the broadcasted identity of the controllable unit.