All IPC monitors are encased in a conducting shield to minimize electrostatic pickup.
For the standard models, one end of the secondary, the case, and the connector are tied to the same potential, and the monitor is grounded at the scope. To avoid ground loops it is advisable to ground the monitor only through the coax cable and provide insulation between the monitor and ground.
For high voltage applications where a flash-over between monitor and current-carrying conductor is a possibility, we recommend that the monitor itself be grounded via two 1/4-20 threaded holes in the mounting bracket. In this case an insulating connector should be specified to provide electrical insulation between the monitor winding and ground.
For conditions of extreme electrical noise, double-shielding can be supplied.