Abstract: An electrical insulator composed of one or more electrical insulating skirts or sheds or shells; at least some of which skirts or sheds or shells have embedded therein or otherwise associated therewith a permanent magnet (usually annular in shape) that serves to create a magnetic field region through which an arc, in the event of incipient flashover, must pass as it proceeds radially from one terminal of the insulator to the other terminal thereof. The magnetic field is oriented to have a component at the surface of the insulator, that is orthogonal to said surface. As the arc passes through the field region it is deflected sideways or circumferentially and rotates in a circle, thereby dissipating the energy in the arc. The effect of the field can be increased by having two or more annularly shaped permanent magnets embedded in the insulator and spaced radially from one another, successive magnets having oppositely directed fields to the magnet or magnets immediately adjacent the same.

Abstract: An electrical insulator composed of one or more electrical insulating skirts or sheds or shells at least some of which skirts or sheds or shells have a plurality of discrete conductive regions at one surface thereof, the discrete conductive regions being appropriately arranged and sufficient in number to intercept an arc in the event of incipient flashover from proceeding radially past the discrete conductive regions, thereby to prevent said flashover.