Electrical Diagnostic Surveys
Short Circuit Current Calculations

EDS can provide Short-Circuit Analysis in accordance with IEEE std 551-2006; Recommended Practice for Calculating Short-Circuit Currents in Industrial and Commercial Power Systems (Violet Book), in accordance IEEE std 399-1997; Recommended Practice for Industrial and Commercial Power Systems Analysis (Brown Book), IEEE std 141-1993; Recommended Practice for Electrical Power Distribution for Industrial Plants (Red Book), and ANSI C37.010, C37.13, C37.5. Short-circuit current values are calculated at each bus location on the one-line diagram. Three-Phase, Single Line-to-Ground, Line-to-Line, Line-to-Line-to-Ground faults shall be analyzed.

The two main standards used for short circuit analysis would be from ANSI C37.010 and IEC 60909. These standards are widely used for calculating short circuit fault values in electrical power systems. Both are suitable for meeting the requirements of the NEC 110 labeling requirements for fault current values, as well as electrical equipment and protective device selection and application.

Most commercial software packages allow the choice of either the ANSI or IEC methods. Most packages default to the ANSI standard for baseline analysis. The ANSI method is great for balanced fault calculations which are more widely used for design. IEC allows greater flexibility for multiple faults as well as unbalanced fault calculations.

Short circuit calculations are necessary for the design process when specifying electrical equipment and protective devices, as well as the back bone of arc flash hazard calculations. When calculating arc flash hazards throughout any facility, short circuit calculations are first performed. This calculation determined the bolted fault current at a location which is then used to derive arcing fault current.

See our IEEE 1584 page for more information on Arc Flash Calculations or Arcing Fault Current.

Short Circuit Current Calculations
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