30/7/2016 Page 1 TiSoft ElectricalDesign LineDetailedCalculationIEC60364 Line analytical calculations according to IEC 60364 Switchboard - Working voltage DB2 , Switchboard , 3~400V 50Hz Line No 7 , LOAD 7 Load electrical characteristics Number of phases / Rated voltage U 3~400 V Installed power Pinst 50,00 kW Simultaneity η 1,00 Absorbed power P 50,00 kW Power factor cosφ 0,85 Load type Sockets Design current Ib=P/(1.732·U·cosφ) 84,9 A Circuit protection device Protection device nominal current In 100 A Basic condition holds Ib < In < Iz 84,9 < 100 < 105,6 Installation Method, Correction factors Number : 72 (Table A.52.3) Sheathed single-core or multi-core cables direct in the ground – without added mechanical protection Reference Method : D2 Ground Temperature, Table B.52.15 = 25°C Soil-thermal Resistivity = 3,0 K*m/W Number of circuits = 6 Cables are touching Ambient temperature correction factor , Table B.52.15 k1 0,95 Grouping correction factor , Table B.52.18 k2 0,50 Cable cross-section sizing Cable NYY-O 3X150+70 sm + NYY 1X70 rm Maximum permissible conductor temperature θcond,max 70,0 °C Table with current rating of cables under reference conditions Table B.52.4 col. 8 Current rating of cable from the above table Ir 247,0 A Current rating of cable under operation conditions Iz = Ir·k1·k2 105,6 A Cable losses Ploss 2,7 W/m Cable conductor temperature θcu 54,1 °C Cable cross-section D 43,0 mm Cable weight G 5.750,0 kg/km Cable check to voltage drop Direct current resistance at 20°C (IEC 60502-1) R20 0,124 Ω/km Corrected direct current resistance at 70°C R 0,148 Ω/km Cable inductive reactance (IEC 60502-1) X 0,100 Ω/km Cable length L 15,0 m Cable impedance Z = L·(R·cosφ + X·sinφ) 0,003 Ω Cable voltage drop ΔU = 1.732·Ib·Z 0,39 V Cable voltage drop % ΔU% = (ΔU·100)/U 0,10 % Cable permissible voltage drop ΔUmax% 2,00 % Voltage drop % from the beginning of the installation ΔUtotal 0,51 % Short-circuit endurance Prospective short circuit current on switchboard busbars Ik 10,04 kA Conductor cross-section q 150,0 mm² Material coefficient for copper conductors k 115 A/mm² Short-circuit permissible cut time t 5s Minimum conductor cross-section qmin mm² Tripping check Protection device characteristic curve MCB B Instantaneous element operation current I5 500 A Source impedance r = U/Ik 0,02291 Ohms Short-circuit current at the end of the line Io = U/(r+Z) 8.990 A