Low voltage welding circuit with non-conductive ground connector

Abstract From the Canadian patent

A protective ground connector for establishing a direct ground connection in response to a fault voltage in a welding circuit. A pair of smooth-faced metal blocks are clamped in face-to-face relationship with each other with a relatively thin shim of electric insulating material clamped between the opposed faces of the blocks. One of the blocks is electrically connected to a circuit to be monitored the other block is electrically connected to ground. The electrical characteristics of the shim are such as to electrically insulate the two blocks from each other in the face of normal circuit voltages and to break down in response to a fault voltage in the monitored circuit to thereby establish …