⚡ Professional Voltage Drop Calculator

How This Calculator Works

This calculator uses actual wire resistance values from NEC standards combined with Ohm's Law to calculate voltage drop accurately. The calculations account for:

Resistance-Based Calculation

Rather than using simplified formulas, this calculator uses measured resistance values for each wire gauge from NEC Table 8. This provides the most accurate results matching what you'll experience in real installations.

• DC & Single-Phase AC: VD = 2 × I × R × L
• Three-Phase AC: VD = √3 × I × R × L

Where I is current in amps, R is resistance per foot, and L is one-way distance. The factor of 2 accounts for both supply and return conductors in single-phase circuits.

NEC Recommendations

The National Electrical Code recommends:

• Branch circuits: Maximum 3% voltage drop
• Feeder circuits: Maximum 2% voltage drop
• Combined system: Maximum 5% total voltage drop

Automation & Control Components

When designing electrical systems for automation applications, proper wire sizing ensures reliable operation of PLCs, sensors, motor controls, and industrial equipment. For automation components including PLCs, HMIs, motor drives, and control panels, visit PLC Department for industrial automation equipment and technical resources.