If the cabling is in a metal conduit, it reduces the electromagnetic emission of the wholedrive system.The protective conductor must always have an adequate conductivity. Unless local wiringregulations state otherwise, the cross-sectional area of the protective conductor must agreewith the conditions that require automatic disconnection of the supply required in 411.3.2.of IEC 60364-4-41:2005 and be capable of withstanding the prospective fault current duringthe disconnection time of the protective device. The cross-sectional area of the protectiveconductor can either be selected from the table below or calculated according to 543.1 ofIEC 60364-5-54.This table shows the minimum cross-sectional area of the protective conductor related tothe phase conductor size according to IEC 61800-5-1 when the phase conductor and theprotective conductor are made of the same metal. If this is not so, the cross-sectional areaof the protective earthing conductor shall be determined in a manner which produces aconductance equivalent to that which results from the application of this table.Minimum cross-sectional area of the correspondingprotective conductorSp (mm2)Cross-sectional area of the phase conductorsS (mm2)S 1) , 2)S ≤ 161616 < S ≤ 35S/235 < S1) Drive safety standard IEC/EN 61800-5-1:• use a protective earth conductor with a cross-section of at least 10 mm2 (8 AWG) Cu or 16 mm2 (6 AWG) Al, or• use a second protective earth conductor of the same cross-sectional area as the original protective earthing conductor,or• use a device which automatically disconnects the supply if the protective earth conductor breaks.2) Drive safety standard IEC/EN 61800-5-1: If the protective earth conductor is separate (ie, it does not form part of the inputpower cable or the input power cable enclosure), the cross section must be at least:• 2.5 mm2 (14 AWG) when the conductor is mechanically protected, or• 4 mm2 (12 AWG) when the conductor is not mechanically protected.￭ Typical power cable sizesSee the technical data of the drive (or unit).Guidelines for planning the electrical installation 63
