Selectivity Tab

  • Selectivity check between the backup protection from supplier and the main device: This box needs to be checked if the user wants ElectricalOM to monitor the selectivity between the DNO's protection device and the main protection device at the origin of the modelled system. If not checked, ElectricalOM will ignore the protection from the DSO while carrying the selectivity study. Please refer to Selectivity Study Module Tab for more details about selectivity.
  • Warning when the manufacturer's selectivity tables are not presented:Electrical OM uses manufacturer's data while carrying calculations unless generic items are picked and sometimes this data may not be complete. If this box is ticked, ElectricalOM will warn the user that selectivity data is missing and the selectivity study shall be done by the user by other means like referring to manufacturer's data sheet. If this option is not checked there will be no warning about missing data. If you want any manufacturer or any missing data from an existing manufacturer to be added to ElectricalOM's database, please contact support at
  • Enable Min-Max Curve band for Electronic Adjustable Devices: This option is applicable only for branded devices and will not affect Generic devices. If an MCCB is selected as a protection device with adjustable settings, the user may opt to see the Time vs Current curve as a line rather than a band. In this case, this tick box needs to be unticked, so ElectrciaOM will set this as default setting and Time vs Current curves will be shown as a line.

  • Always perform earth fault selectivity checks even if no earth fault specific devices are presented: This option is provided so the user may opt to still check selectivity during an earth fault if no RCD is used on a circuit. If this box is unchecked, then, ElectricalOM will not check selectivity during an earth fault if no RCD is used.