RjX Engineering creates a software model of the customer’s facility distribution system. This model contains all possible sources of fault current as well as system impedances needed to calculate available fault current levels throughout the system. The short circuit study includes:
Calculated fault currents are used in coordination and arc flash analysis
Comparison of fault currents to equipment short circuit current ratings (SCCR) to determine equipment short circuit adequacy.
Calculation of fault currents at all locations in the system
Short Circuit Analysis will determine maximum available fault current levels at all locations in the system. In addition, the report will inform as to whether or not each location is properly rated for the fault current calculated.
For equipment to be “adequately” rated for short circuit currents, the interrupting rating of the equipment must be greater than the available fault current.
Equipment is “inadequately” rated when the interrupting rating is less than the available fault current. In this case, the behavior of the equipment under fault conditions cannot be ensured to meet manufacturer standards. This can result in dangerous conditions for the equipment when experiencing a fault.
The software model that is built calculates worst case fault current based on industry accepted ANSI and IEEE standards. The software handles all calculations based on the appropriate algorithms defined in the standards and the results provided are included in the study both for maximum short circuit calculations as well as equipment evaluation.
