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Fault Current, Voltage Drop, and Arc-Flash Calculations

Turn to Design Master Electrical for your complete electrical design and drafting solution. It calculates the fault current, voltage drop, and arc-flash in your project.


Design Master Electrical uses the same panels and transformers you create for a project’s one-line diagram, and panel load calculations, to calculate fault current and voltage drop. Arc-flash is calculated based upon the settings for the panels and transformers and the calculated fault current. Schedules display the results of those calculations on your drawing.

Design Master Lets You Customize

Our default schedules are accepted during most plan reviews. However, you can customize it easily when your specific plan reviewer asks for additional information.

Design Master Can Include Motor Contributions

With Design Master, you’ll never again say, “It’s too much work to include motors in our fault value calculations.” Add every motor to your project; Design Master will perform the calculations automatically. Then you can select the right AIC rating for your panels. Design Master empowers you to keep costs as low as possible. No more spending more for panels with a higher AIC rating just to be safe.

The fault calculation is performed using industry standard IEEE Std 242-2001.

Design Master Calculates Voltage Drop on both Feeders and Branch Circuits

Design Master bases its feeder voltage drop results on the panels and transformers in your project, the sizes of the feeders, and their distances from each other. You can manually specify the distance between panels. Or you can place the panels on your drawing and have Design Master calculate the distances for you.

Design Master also bases the branch circuit voltage drop on the number of devices connected to each circuit and their location on the drawing.

The voltage drop is calculated using industry standard formulas.

Design Master Highlights Non-compliant Voltage Drops

Design Master makes it easy to identify when there’s a problem in your electrical design. It highlights any circuit or feeder that exceeds the maximum voltage drop allowed by the NEC (3% for the circuit or the feeder, 5% for the sum of the two). Just modify your design to reduce the voltage drop, and Design Master recalculates.

Design Master Calculates Arc-Flash

Design Master lets you specify the factors that influence arc-flash incident energy for each panel, from electrode configuration to working distance. Arcing times can be based upon time-current curves for each breaker or set manually. You can also print warning labels to be placed on the panels in the field. The calculations are performed using industry standard IEEE Std 1584-2018.

“Design Master Software has helped our business to keep going and make a profit in situations where our competitors just couldn’t--that’s been a huge asset.”

Crawford Murphy, founder
Red Claw Engineers
Canton, GA

Next feature: Selective Coordination

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