Abstract: An electrical resistance heater (12) has an elongate electrical heating coil (C) with a plurality of convolutions (C1, C2). An electrical insulator (10) supports the convolutions and includes an insulator body (18) mountable to a support frame (19). A generally circular projection (20) extends from one side of the body and is integrally formed therewith. A generally arcuate section (26, 28) of the projection, on opposite sides of the projection, is spaced from an adjacent surface (30, 32) of the body. A notch (34, 36) is formed by the respective surfaces of the body and the projection for respective coil convolutions (C1, C2) to be received in the respective notches. The upper end (42, 44) of the faces (38, 40) of the projection are tapered outwardly from the top of the projection to facilitate coil installation. A shoulder (30s, 32s) formed on the insulator body adjacent each notch helps retain the coil convolutions in the notches.

Abstract: In a metallic sheathed electric heating element assembly having a resistance element, a sheath surrounding the resistance element, pulverulent electrically insulating material within the sheath and surrounding the resistance element, the insulating material being tightly compacted and extending within the sheath short of an open end thereof, and a terminal pin electrically and mechanically connected to an end of the resistance element within the compass of the sheath, the terminal pin is made in two parts, an inner part to which the resistance element is connected, and an outer part spaced from the inner part, and a thermal switch or cut off electrically connected to and in series between the inner and outer parts of the pin within the sheath but spaced toward the open end from the compacted insulating material, the thermal switch being in good thermal contact with the inner part of the terminal pin.

Abstract: A water heater with a plastic tank is provided with an electric immersion heating element assembly having a mounting plug in which is mounted a sheathed heating element having two generally parallel legs and a bight portion. A well projects from the mounting plug along and substantially parallel to the legs in heat exchange relation therewith and contains a thermal cutoff adapted to be electrically connected in series with the first end of a two-ended electric resistance element in the sheathed heating element. A thermally conductive bridge mechanically and thermally connects the legs of the sheathed heating element to the well. The legs of the sheathed heating element are bent back upon themselves and a bracket, connected to the two reaches of at least one leg, permits relative axial movement but prevents lateral movement of the reaches of the legs with respect to one another. The mounting plug is made of solid copper or copper alloy, as is the sheath and well.