Sym Current app for iPhone and iPad

Calculating short-circuit currents in panelboard bus, taking into account the feeder and motors contribution; in accordance with ANSI IEEE Std 551-2006.

Calculations based on the following assumptions:

•Three-phase ac system, balanced, 60 Hz.
•Three-phase bolted fault.
•The values of short-circuit current are in terms of RMS symmetrical amperes.
•Only considers the contribution of induction motors.
•Motors contribution is on the basis of percentage of the total load.


Specify the necesary data for:

-The utility system.
-The secondary unit substation transfomer
-The feeder (allows conductors in parallel)
-The load (total load and motors load in %)

The app suggests typical values for short-circuit duty (MVA) and the X/R ratio of the utility system, also suggests the value of Z% for the transformer, but the user can specify the value of nameplate