Voltage Drop at 600V (Three-Phase AC)
600V systems are common in heavy commercial and industrial facilities where long feeder runs and high loads are present.
Why 600V Systems Need Attention
At 600V, voltage drop matters less on short runs but becomes significant over long feeders in large buildings or industrial plants.
Example Calculation
For a 600V Three-Phase AC circuit at 120 A over 250 ft using 3/0 AWG copper:
Voltage drop = 1.732 x I x R = 1.732 x 120 x (ohms per ft for 3/0 AWG x 250 ft)
Common Applications at 600V
- Heavy industrial motors
- Large mechanical systems
- Long building feeders
Common Questions
What is the acceptable voltage drop for a 600V circuit?
Most engineers target 3% or less on branch circuits and 5% total (feeder plus branch). These are general guidelines, not hard NEC requirements. Check your local code.
What wire gauge should I use for a 600V circuit?
It depends on load current and run length. Use the voltage drop calculator with your specific values. A longer run or heavier load requires a larger gauge.
Does voltage drop affect safety?
Excessive voltage drop can cause motors to overheat, breakers to nuisance-trip, and equipment to malfunction. It is not just an efficiency issue.
Can I use aluminum wire on a 600V circuit?
Aluminum is commonly used for larger feeders (service entrances, subpanel feeds). For small branch circuits, copper is generally required. Aluminum has higher resistance than copper for the same gauge, so voltage drop is worse for the same wire size.