A powering arrangement for an undersea cable system provides that each branch of the system is supplied with a current equal to half of the current in the trunk. By coupling both branches to the trunk, the current adds at the branching unit. Upon occurrence of a power path fault in any branch, a virtual ground moves to the site of the fault. In addition, an image virtual ground moves to a similar point in the branch that does not have the cable fault. As a result of this implementation, the cable power system is able to tolerate at least one fault in a branch without necessitating repair, and can tolerate some multiple branch faults depending upon their location. In contrast to the operation of existing power-switched branching units, the fault-tolerant branching unit does not require down-powering and re-powering in order in order to change the power configuration, e. g. , to allow a virtual ground to be re-located at shunt fault sites that occur in either trunk or branches. Moreover, even with a branch shunt fault or cable break, the fault-tolerant branching unit allows for power to be removed from the faulted branch for repair without having to first power down the other two legs.