Table

Duct Heater Line Current Multipliers

Duct Heater Line Current Multipliers reference with assumptions and boundary notes.

Reference boundary

Multiplier reference only. Confirm heater nameplate voltage, phase, steps, and controls.

Reference table

Use amps-per-kW multipliers for duct heater current estimates by voltage and phase.

Formula basis uses single-phase and balanced three-phase power equations for resistive heaters.
Voltage and phaseAmps per kWFormulaExample
120 V 1-phase8.331000 / 1205 kW x 8.33 = 41.7 A
208 V 1-phase4.811000 / 2085 kW x 4.81 = 24.0 A
240 V 1-phase4.171000 / 2405 kW x 4.17 = 20.8 A
600 V 3-phase0.961000 / (sqrt(3) x 600)30 kW x 0.96 = 28.9 A
Use notes
  • Use this table for preliminary reference and arithmetic checks only.
  • Confirm equipment ratings, product markings, installation conditions, utility requirements, and the local authority requirements before design or field use.