Conductor Fault Current Calculator

Wherever electrical conductors are used, it is important to ensure that they are properly rated not only for continuous current but also for short circuit (aka fault) current conditions. When installed in code-covered circuits, for example, motor operated valves or other electrical equipment, conductor size is typically based on continuous current instead of fault current. This is because the primary goal of conductor sizing for these applications is to prevent overheating and insulation failure during normal, continuous operation, and short-circuit protection is managed by circuit breakers. However, for non code-covered circuits, such as AC mitigation, isolation joint protection, gradient control mats or tank grounding, where there are no localized circuit breakers to protect the circuit from faults, all equipment in the circuit, including the conductors, must be rated to survive the maximum fault current that could occur.

Charts of short circuit current limits for common copper conductors are provided in NACE SP0177-2019. But Dairyland’s conductor fault current calculator makes these calculations easy and includes Dairyland test results (at 30 cycles/60 Hz) on Dairyland MTL conductors. Our testing has shown that some conductors endure fault currents higher than that specified by NACE SP0177.

To use the calculator, enter the conductor size, insulation type and fault duration in seconds. The calculator will display the conductor fault current rating based on NACE SP0177-2019 and, if available, based on Dairyland fault testing for comparison.

If you have any questions, please contact us at techsupport@dairyland.com.