Fault Levels Tab

  • Voltage variation factors to be used during phase fault current calculations (IEC 60909): In order to calculate minimum and maximum fault currents, user may wish to compensate voltage fluctuations.To enable the user to take into account these variations, ElectricalOM provides two options for Cmax, which are 110% and 105% of the supply value, and one option for Cmin as 95% of the supply value. These can be selected by ticking the boxes next to these options, however, only one box can be ticked for Cmax value.

With Amendment 3 of 17th edition, Cmin factor is also introduced to BS7671. If a 230V single phase supply is taken as an example, then:

  • Cmin =0.95        corresponds to        218.5V
  • Cmax =1.1        corresponds to        253V
  • Cmax =1.05 corresponds to        241.5V
  • Default - Enable Current Limiting Effect: This option will enable the current limiting feature for capable devices as the default setting. See Protective Devices Tab for further details about current limiting.