Extension Cord Power Loss Calculator

How Extension Cord Power Loss works

The calculation starts with loss = I²R. Extension Cord Power Loss uses Load current, Round-trip cord resistance to report Cord loss.

With the loaded values, cord loss evaluates to 60.48 W. Preserve the baseline before changing a value. Use Current-Limiting Impedance Calculator as the follow-up for required impedance.

Inputs for Extension Cord Power Loss

Load current and Round-trip cord resistance belong to Extension Cord Power Loss. Keep source units with load current. Remaining box volume belongs in the separate Junction Box Fill worksheet.

The preset case is instructional rather than prescriptive. Enter the applicable electrical data.

Load current

Example entry: 12 A.

Round-trip cord resistance

Example entry: 0.42 Ω.

Reading the Extension Cord Power Loss result

This output represents Extension Cord Power Loss.

Finish the selection with standard sizes, operating limits, and transient review.

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 load current.

Keep the same electrical reference points across saved cases. For required conductor area, use Wire Gauge Calculator.

Limits of this calculation

Coiled cords and warm surroundings reduce cooling. If the next question concerns wire resistance, open Wire Resistance Calculator.

A complete system can contain effects that this equation does not represent. Unentered effects remain outside Extension Cord Power Loss.

A useful Extension Cord Power Loss comparison

Record cord loss before testing a different load current value.

Document the alternate load current source.

Questions about Extension Cord Power Loss