Abstract: For connecting a shunting impedance to a contact rod of a circuit breaker, there is provided an impedance contact assembly comprising a metal ring, two slots in the ring at diametrically-opposed locations, and a U-shaped metallic spring member having two spaced-apart arms and a bight portion. The spring member, which is positioned with its bight portion in one slot and the free ends of its arms in the other slot, has a resilience tending to bias the arms apart and against the walls of said other slot. The contact rod has a path of movement that extends between the spaced arms so that the arms slidably engage the contact rod at its opposite sides as the contact rod moves along this path.

Abstract: An underground electrode adapted for ground conduction of electric current in an environment of saline and oleaginous fluids and under high hydrostatic pressure comprises a hollow tubular electrode having a cable terminal at its upper end and affixed to the lower end of an insulating cable conduit. A fluid supply conduit surrounding the cable conduit supports a permeable enclosing basket which surrounds the electrode and controls flow of fluid electrolyte over its surface.

Abstract: A high voltage d-c cable is tested by first disconnecting the normally-grounded sheath of the cable from ground and providing insulation between the sheath and ground. The sheath is then biased to a predetermined bias voltage that is of an opposite polarity with respect to ground as the normal operating voltage of the cable conductor. The conductor is then energized with current and test voltage derived from its normal source. This test voltage is of the same polarity with respect to ground as the normal operating voltage of the cable conductor and of a magnitude approximating said normal operating voltage, whereby the difference between said test voltage and said bias voltage is applied to the cable insulation between the cable conductor and sheath.