A compact electrostatic precipitator is designed specifically for use in connection with eliminating particles from crankcase emissions of a Diesel engine. Such emissions may carry solid soot particles as well as suspended oil droplets. The electrostatic precipitator has an electrode housing in which a high voltage electrode is mounted, and the emissions from the crankcase of a Diesel engine are passed across the electrode to an outlet. A high voltage power supply is mounted in a separate housing, and the output of the high voltage power supply is connected to the electrode only when the electrode housing and the power supply housing are properly mated, to thereby disable the high voltage connection to the electrode when the power supply housing is removed. A current limiting device is used in the circuit to the power supply to prevent high currents from being carried if any arcing occurs, and a normally open switch is closed to provide input power to the high voltage circuitry only when the power supply housing and the electrode housing are mated.