Quick Voltage Drop Calculator

Voltage Drop Calculator

This voltage drop calculator is for Pyrotenax Copper-Sheathed MI Wiring cable.

* Required Field


*   amperes

*   awg


*   %

*   feet


  • Ensure all the applicable requirements of the National and Local Electrical Codesare met.
  • If the voltage drop is over the desired limit, select a larger cable and repeat. Alternatively, use parallel runs of smaller cable, calculating voltage drop on the reduced current carried by each.
  • For fire pump motors, check that the voltage drop does not exceed 5% @ 115% rated current; and does not equal or exceed 15% at locked rotor current, including the drop in the motor/generator.
  • These calculated voltage drops represent line to line voltage drop in a 3-phase system. To estimate the single phase voltage drop, simply multiply the 3 phase line to line voltage drop by 1.16.
  • In the rare instances where line to neutral voltage drop in a three phase system is required, multiply the 3 phase line to line voltage drop by 0.58.
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