Electrical discharge machining (debris) to be carried away and the insulating properties of the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is commonly referred to as "flushing." Also, after a current flow, the difference of potential between the electrodes is restored to what it was before the breakdown, so that a new liquid dielectric breakdown can occur. The erosive effect of electrical discharges was first noted in 1770 by English physicist Joseph Priestley. Two Russian scientists, B. R. Lazarenko and N. I. Lazarenko, were tasked in 1943 to investigate ways of preventing the erosion of tungsten electrical contacts
Electrical room unauthorized persons; these rules are especially strict where equipment within the room has exposed live terminals. Regulations may require two separate means of exit from a room where the power rating of circuits exceeds some threshold, to allow for quick exit in an emergency. Rooms containing oil-filled equipment may be required to have fire-resistant construction or active fire suppression equipment in the room and may be designated as an "electrical vault". Since power distribution often requires large numbers of electrical cables, special measures for fire resistance of cables and cable trays may be also specified by regulations. In industrial buildings