SECTION OF ELECTRIC NETWORK Russian patent published in 1998 - IPC

FIELD: electrical engineering, gears for neutral earthing of industrial electric installations and production facilities. SUBSTANCE: extended grounding electrode with discrete or continuous leak of current, for instance supporting structure of production building or facility, connected in parallel with fourth conductor of cable of electric network by means of protective conductor is used as additional zero protective conductor. Cable is laid in zone limited by two circular cylinders which axes match axis of hypothetical equivalent conductor substituting structure of production building or facility - extended grounding electrode. Optimal distance between cable and axis of equivalent conductor is found from condition of minimum of potential-forming current. EFFECT: reduction of potential of neutral earthing of electric installation to safe values independent of speed of action of protection, minimal material and labor expenditures. 2 dwg