To perform short-circuit calculations, select Calculations | Short circuits from the MagiCAD main menu.

TT3_ShortCircuitCalcs_CalculationDialog

In the Short circuit calculations dialog, select calculation type as three-phase (3~) or single-phase (1~) and define the Voltage (V) and Voltage factor (c).

Next, select the Calculation Range. With three-phase calculations, the range is automatically Power distribution network. With single-phase calculation, you can include in the analysis both Power distribution network and load circuits, or restrict the analysis to Power distribution network or Load circuits only.

Object search range allows you to define whether you want to perform the calculation on the Current drawing or on All model drawings.

If you are performing a single-phase calculation, you can set the Circuit/Switchboard range of the calculation to cover either All switchboards or you can decide to manually Select switchboard(s). With three-phase calculations, it is always necessary to Select switchboard(s) manually.

Click Ok. If you did not select All switchboards in the Short circuit calculation dialog above, you can now select the switchboard(s) you want to include in the analysis manually from the plan and examine the results in the Report view. When calculating the entire distribution network, start the calculation from the building’s supply point(s) by selecting the main switchboard(s) you want to include in the calculation. When calculating load circuits, select only the switchboard(s) relevant in terms of the load circuits you want to calculate.

TT3_ShortCircuitCalcs_ReportDialog_ACAD

The three-phase report analyses the power distribution network, displaying cable type, cable length, the R/X ratio, the three-phase peak current value (lp), the three-phase current’s root-mean-square value (lk3p), as well as the type of the protective device and its endurance. A warning is given if the peak current value exceeds the endurance of the protective device.

TT3_ShortCircuitCalcs_ReportDialog_Revit

The single-phase report displays cable type, cable length, the single-phase root-mean-square value (lk1p), tripping time defined for the protective device, tripping current of the protective device, and the maximum allowed cable length with the current cable type/protective device combination.