Abstract: A potential indicating device for indicating the presence of a voltage on a connector in a high voltage electrical distribution system, the connector including a conductor, a semiconductive shield and a test point terminal. The device comprises two separate indicator circuits, each energized by a different voltage capacitively coupled to the conductor. When a voltage is present in the conductor, first circuit means transmits a voltage capacitively coupled to the test point terminal to a visible indicator which flashes intermittently, and second circuit means transmits a voltage capacitively coupled to the semiconductive shield to an audible indicator when switching means closes the second circuit means. Preferably switching means comprises a photosensitive transistor normally shielded from light by a removable plug.

Abstract: A protective device for use with a surge arrester to prevent fracturing of the porcelain body of a failed arrester includes a fast-operating switch which shunts a current-limiting fuse. The switch is operated by ignition of a chemical propellant charge, thereby rapidly diverting fault current to the fuse and additionally isolating the arrester from ground. The switch has a moving contact in the form of a gas-driven piston which strikes a separable terminal connected to a ground lead.