# Fault current & arc flash calculation examples

### Short Circuit Calculations

The example explains how to build a single line diagram of the power distribution system using ARCAD's Short Circuit Analytic (SCA V1.0) software program, how to perform short circuit fault current analysis and document the results.

This program, other programs, or hand calculations can be used to perform short circuit calculations. Any method used requires specific data on the power distribution system components. Check Equipment Data for Short Circuit Study page describing the data required by the Short Circuit Analytic software and mobile apps for each type of circuit component and how to obtain the data.

### NFPA 70E based Arc Flash Assessment - three-phase AC system

The example takes you one step at a time through arc flash analysis based on NFPA 70E standard and IEEE 1584 empirical model by means of ARCAD's Arc Flash Analytic (AFA V5.0) software program. Consider low-voltage switch gear with a 10 kA prospective 3-phase bolted fault current at its terminals. The gear is being protected by time-delay fuse located upstream. Incident energy at working distance, arc flash boundary, hazard level, initial blast pressure, arc flash explosive equivalent will be calculated and recommended personal protective equipment (PPE) will be determined based on IEEE 1584 Guide for Performing Arc-Flash hazard Calculations and NPFA 70E year 2015 standard.

### Arc Flash Assessment - DC system

The example guides you through arc flash analysis by means of ARCAD's DC Arc Flash Analytic (DCAFA V3.0) software program. Consider low-voltage panel board with a 25mm gap between conductors, 36 milliseconds time constant 19,048 Amp short circuit fault current at its terminals. The gear is protected by Mersen 1200A 500V DC rated fuse part number A4BQ1200 located upstream. Incident energy at working distance, arc flash boundary and site-specific level of personal protection equipment (PPE) will be determined based on DC arc flash modeling and NPFA 70E Standard for Electrical Safety in the Workplace.

### Single Phase Arc Flash Calculations

Consider 256V AC panelboard with a 25mm gap between conductors, 19,048 Amp 5 X/R bolted fault short circuit current at its terminals. The gear is protected by Mersen 1400A 600V AC rated fuse part number A4BQ1400 located upstream. Incident energy at working distance, arc flash boundary and site-specific level of personal protection equipment (PPE) will be determined using ARCMASTER V1.0 software program based on AC arc flash modeling and NPFA 70E Standard for Electrical Safety in the Workplace.

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