Abstract: The present invention utilizes a coupling tap that contains two parallel communication paths from the connection at a coaxial cable to a tap output, to which a device can be connected. One path passes high frequency signals of 30-900 megahertz, while the other passes lower frequency communication signals of 0-5 megahertz as well as DC power. Furthermore, each tap may contain a line isolating inductor that, when a particular tap is in use, isolates the portion of the coaxial cable that continues on past the tap in use for signals from 0-5 megahertz. This eliminates reflections and other line disturbances from entering the tap in use.

Abstract: A ground-fault circuit interrupter is provided with an additional current-sensing element that responds to a net value of current through the power wires in an ac circuit. The winding may be wound on a ferromagnetic core of its own or it may be placed as a separate winding on a core that is used to sense imbalance in a GFCI. In the latter case the extra winding must be insulated electrically from the main sense winding. The additional coil is connected to a rectifying diode and a capacitor, so that an imbalance of current in the power wires charges the capacitor. The voltage thus developed across the capacitor is used to operate the tripping mechanism of the ground-fault circuit interrupter. The fault-powered signal thus attained in the added winding will enable the GFCI to operate despite the existence of heavy fault currents that reduce the operating voltage to the rest of the GFCI to a level that would otherwise prevent its operation.