Encapsulated high voltage rectifier for use on the phase tell meteres 6702/6706. When used in conjuction with the phase tell it will enable the operator to perform the following tests on systems up to and including 35 kV phase to phase: 1. Test sections of underground cable to determine the integrity of insulation, i.e. failed cables; 2. Determine if all grounds have been removed after completion of working on a de-energized underground system.