Calculate the voltage drop for installing wire at certain lengths.
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Voltage Drop Calculator
- 1. Examples for parallel runs: 120/240V single phase system with single black-red-white conductors (installed in single conduit) select "single set of conductors", 120/208V 3phase system with 2 conductors per phase and neutral (installed in 2 parallel conduits) select "2 conductors per phase in parallel", dc system with 3 positive and 3 negative conductors select "3 conductors per phase in parallel".
- 2. Voltage drop for ac systems should total no more than 5% under full load conditions. Drop may be significantly larger during surge or motor starting conditions -- sometimes in the 15% to 25% range if other devices on the system can withstand this momentary dip. Voltage drop for dc systems should be designed as low as possible or less than 2%.
- 3. For most 120/240V systems using cables of adequate ampacity, voltage drop is not a concern unless cable lengths are well over a hundred feet.