sec.191Earth fault current limitation

### sec.191 Earth fault current limitation The electrical engineering manager for an underground mine must ensure each electrical circuit at the mine has an earth fault current limitation of not more than— for a circuit supplying equipment and cables in an ERZ1 at the mine—5A; or for a high voltage circuit not mentioned in paragraph (a) —10A; or for a low voltage circuit not mentioned in paragraph (a) —5A. Subsection (1) does not apply to the following— an intrinsically safe circuit; a circuit operating at not more than 55V to earth and fully contained in a NERZ or an explosion-protected enclosure; a circuit isolated from earth. The electrical engineering manager must ensure— the neutral point of a transformer secondary winding for an impedance earthed electrical system at the mine is distributed to only the neutral earthing impedance; and each part of an impedance earthed, or insulated neutral, electrical system at the mine has a phase-to-earth insulation level equivalent to the phase-to-phase insulation level for the electrical system. (sec.191-ssec.1) The electrical engineering manager for an underground mine must ensure each electrical circuit at the mine has an earth fault current limitation of not more than— for a circuit supplying equipment and cables in an ERZ1 at the mine—5A; or for a high voltage circuit not mentioned in paragraph (a) —10A; or for a low voltage circuit not mentioned in paragraph (a) —5A. (sec.191-ssec.2) Subsection (1) does not apply to the following— an intrinsically safe circuit; a circuit operating at not more than 55V to earth and fully contained in a NERZ or an explosion-protected enclosure; a circuit isolated from earth. (sec.191-ssec.3) The electrical engineering manager must ensure— the neutral point of a transformer secondary winding for an impedance earthed electrical system at the mine is distributed to only the neutral earthing impedance; and each part of an impedance earthed, or insulated neutral, electrical system at the mine has a phase-to-earth insulation level equivalent to the phase-to-phase insulation level for the electrical system. - (a) for a circuit supplying equipment and cables in an ERZ1 at the mine—5A; or - (b) for a high voltage circuit not mentioned in paragraph (a) —10A; or - (c) for a low voltage circuit not mentioned in paragraph (a) —5A. - (a) an intrinsically safe circuit; - (b) a circuit operating at not more than 55V to earth and fully contained in a NERZ or an explosion-protected enclosure; - (c) a circuit isolated from earth. - (a) the neutral point of a transformer secondary winding for an impedance earthed electrical system at the mine is distributed to only the neutral earthing impedance; and - (b) each part of an impedance earthed, or insulated neutral, electrical system at the mine has a phase-to-earth insulation level equivalent to the phase-to-phase insulation level for the electrical system.