In a two-stage, electrostatic precipitator for extracting airborne particles, charged plates are electrically connected to each other and physically separated from each other by ferrite spacers so that an impedance of the spacers limits an amount of arc discharge current that will flow when an arc discharge occurs from one of the charged plates. Ferrite spacers can also be provided to electrically connect and physically separate grounded plates in the precipitator. In addition, aluminum spacers can be provided to adjust the impedance of the series of spacers through which an arc discharge current flows, so that the current is a minimum necessary amount for an arc detection circuit to detect.