Abstract: A component of an electrical system capable of operation at any of two or more different nominal normal operating voltages is protected from a transient overvoltage condition by an apparatus having at least one phase-to-ground array of surge protection devices (SPDs) connected in series with one another to define a series of tap points on opposite sides of the SPDs and having at least two sets of electrical conductors for coupling the electrical system to a user-selectable one of the tap points which corresponds to a desired one of the nominal operating voltages. An array of capacitors connected electrically in series with one another is connected between each of the tap points and a monitoring circuit to provide impedance for dropping each nominal operating voltage to a suitable voltage for powering the monitoring circuit with low energy loss.

Abstract: A method and apparatus for surge protecting an electrical load coupled to an AC power distribution system of the type including a distribution panel containing at least one branch circuit overcurrent interrupter. The load is coupled to a surge protection circuit contained within a housing mountable entirely inside the panel. The circuit generates a signal indicative of an operating condition of the circuit. That signal is carried to an externally viewable visual indicator by way of an electrical path which is coupled between the circuit and the indicator and can be physically located entirely within the interior of the distribution panel.

Abstract: A polyurethane system especially adapted for surge suppression comprising the reaction product of:A1. Castor oil2. A molecular sieve having the composition M.sup.1.sub.12 (Al O.sub.2).sub.12 (Si O.sub.2).sub.12, wherein M.sup.1 is an alkali cation3. Polydimethyl siloxane4. Hindered phenol antioxidant5. Tetraisopropyl diphenyl carbodiimide6. 10, 10.sup.1 -oxybisphenoxarsine7. Alumina trihydrate andB8. 4, 4.sup.1 diphenylmethane diisocyanate;the system having a Shore hardness of 80 to 90.