Physics Calculators

#1 Free Voltage Drop Calculator 2025

3 weeks ago
2 mins
26 Views

Interactive Voltage Drop Calculator

How to Use This Calculator

This calculator helps determine the voltage drop across an electrical conductor.

  • Select the conductor material (Copper or Aluminum).
  • Choose the wire size from the AWG (American Wire Gauge) dropdown.
  • Enter the one-way length of the conductor in meters (m).
  • Input the current flowing through the conductor in Amperes (A).
  • Enter the system's source voltage in Volts (V).
  • Select the electrical phase (Single Phase or Three Phase).
  • Click "Calculate Voltage Drop".
  • Results, including a step-by-step solution, will be displayed below.

Note: Calculations assume a conductor temperature of 20°C (68°F) and a power factor of 1 (for AC circuits).

Theory: Understanding Voltage Drop

Voltage drop is the decrease in electrical potential along the path of a current flowing in an electrical circuit. Wires, no matter how conductive, have some resistance. As current flows through this resistance, energy is lost, typically as heat, resulting in a lower voltage at the end of the wire compared to the source.

Why is it important?
  • Equipment Performance: Excessive voltage drop can cause equipment to malfunction, run inefficiently, or fail prematurely.
  • Energy Waste: Lost voltage is wasted energy, converted into heat in the wiring.
  • Safety: Overheating wires due to high resistance and current can be a fire hazard.
Factors Affecting Voltage Drop:
  • Wire Material: Copper is more conductive (lower resistivity) than aluminum.
  • Wire Size (Gauge): Thicker wires (smaller AWG number) have less resistance.
  • Wire Length: Longer wires result in greater voltage drop.
  • Current: Higher current increases voltage drop (V=IR).
  • Temperature: Higher temperatures increase wire resistance (not an input in this basic calculator but an important factor in real-world scenarios).

National Electrical Code (NEC) often recommends a voltage drop of 3% or less for branch circuits and 5% or less for the total of feeder and branch circuits.

Formulas Used

The following formulas are used (assuming DC or AC with Power Factor = 1):

  • 1. Resistance of a single conductor (R):

    R = (ρ × L) / A

    • ρ (rho) = Resistivity of material at 20°C (Ω·m)
    • L = One-way length of the conductor (m)
    • A = Cross-sectional area of the conductor (m2)
  • 2. Voltage Drop (VD):
    • Single Phase:

      VD = 2 × I × R

    • Three Phase (Line-to-Line VD):

      VD = √3 × I × R    (√3 ≈ 1.732)

    • I = Current through the conductor (A)
    • R = Resistance of a single conductor (Ω) from step 1
  • 3. Voltage at Load (Vload):

    Vload = Vsource - VD

  • 4. Percentage Voltage Drop (%VD):

    %VD = (VD / Vsource) × 100%

Calculate Voltage Drop

Shares:

Related Posts