Current-Limiting Impedance Calculator

How Current-Limiting Impedance works

This worksheet evaluates Z = V ÷ Imax. Current-Limiting Impedance uses Source voltage, Maximum current to report Required impedance.

With the loaded values, required impedance evaluates to 4.80 Ω. Use separate cases for competing input values.

Inputs for Current-Limiting Impedance

Source voltage and Maximum current belong to Current-Limiting Impedance. Keep source units with source voltage. Maximum loop impedance can be checked in Fault Loop Impedance Calculator.

Use the defaults to understand the output, then enter the real circuit or energy data.

Source voltage

Example entry: 24 V.

Maximum current

Example entry: 5 A.

Reading the Current-Limiting Impedance result

This output represents Current-Limiting Impedance.

Compare the output with equipment limits and the applicable design margins. Use Extension Cord Power Loss Calculator to a separate cord loss calculation.

Measurement and units

Treat these results as planning arithmetic; conductor and protective-device selection must follow the applicable electrical code and equipment instructions. Check prefixes on source voltage.

Do not compare cases built from different unit prefixes or measurement locations.

Limits of this calculation

Component pulse energy and thermal rating also matter.

Unlisted circuit behavior remains outside the computed result. Unentered effects remain outside Current-Limiting Impedance.

A useful Current-Limiting Impedance comparison

Record required impedance before testing a different source voltage value.

Document the alternate source voltage source.

Questions about Current-Limiting Impedance