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Voltage Drop Distance Calculator

Calculate the maximum conductor run length for an allowable voltage drop (L = (VD × 1000) ÷ (I × R)).

Formula

L = (VD × 1000) ÷ (I × R)

L
Maximum one-way distance, in feet
VD
Allowable voltage drop, in volts
I
Current, in amps
R
Conductor resistance, in ohms per 1000 ft

What this calculator does

Calculates the longest one-way conductor run that stays within an allowable voltage drop.

Use cases

  • Find the maximum run length before voltage drop exceeds a target
  • Plan a circuit layout around an allowable voltage drop budget
  • Check whether an existing run length keeps voltage drop in range

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