High voltage bridge for measurements of cables with grounded sheaths

PRECISION bridge measurements are now in use for measuring the dielectric properties of cables when the current through the dielectric can be conducted directly from the sheath to the measuring apparatus. As a rule, however, these methods cannot be applied to cable with sheaths in electrical contact with ground. There is one method in which bridge measurements are made of all system losses, with and without the test cable connected in the circuit; the difference gives presumably the power loss in the cable dielectric. This method does not give the cable electrical properties (power, power factor, and capacitance) directly, and special precaution must be taken in connecting the cable.