1. What is the Voltage Drop Equation?

The voltage drop equation calculates the reduction in voltage in an electrical circuit due to the resistance of the wire. The Southwire version specifically uses resistance values from their tables for accurate calculations.

2. How Does the Calculator Work?

The calculator uses the voltage drop equation:

Where:

• \( VD \) — Voltage drop (volts, V)
• \( L \) — Length of wire (feet, ft)
• \( I \) — Current (amperes, A)
• \( R \) — Resistance per 1000 feet (Ω/1000 ft)

Explanation: The equation accounts for the round-trip distance (hence the 2× factor) and normalizes the resistance per 1000 feet of wire.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive adequate voltage to operate efficiently and prevents potential safety hazards from excessive voltage drop.

4. Using the Calculator

Tips: Enter wire length in feet, current in amperes, and resistance per 1000 feet from Southwire tables. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use Southwire resistance values?
A: Southwire provides accurate, manufacturer-specific resistance values that account for actual wire characteristics.

Q2: What is an acceptable voltage drop?
A: Generally, less than 3% for branch circuits and 5% for feeder circuits is recommended, but consult local codes.

Q3: Why multiply by 2 in the equation?
A: The factor of 2 accounts for the round-trip path of current (out to the load and back).

Q4: How do I find resistance values?
A: Consult Southwire tables for resistance values based on wire gauge, material, and temperature.

Q5: Does this work for DC circuits?
A: Yes, the equation works for both AC and DC circuits when using appropriate resistance values.