Voltage Drop Calculator

Voltage drop is the reduction in electrical potential as current flows through conductor resistance, converting electrical energy to heat. Every conductor exhibits resistance based on material, cross-sectional area, length, and temperature, causing voltage to decrease from source to load.

Critical Impacts: Excessive voltage drop causes motors to overheat and fail (10% drop = 19% torque loss), lighting dimming and flicker, electronic equipment malfunction, energy waste as I²R heat losses, and code violations. Equipment designed for specific voltages suffers reduced efficiency, shortened lifespan, and operational failures when voltage drops below acceptable levels.

Code Requirements: NEC recommends maximum 3% voltage drop for branch circuits, 5% total from service to furthest outlet. IEC 60364 specifies similar limits. Exceeding these violates code, fails inspection, and risks insurance coverage. Proper cable sizing ensures compliance and reliable operation.

Key Factors: Voltage drop = 2 × L × I × R / 1000 for single-phase, where L is one-way length (m), I is current (A), and R is resistance (Ω/km). Factors include conductor material (copper 30% less resistance than aluminum), wire gauge (larger = lower resistance), circuit length (proportional relationship), load current (doubling current doubles drop), temperature (copper resistance increases 0.4%/°C), and power factor in AC circuits.

Mitigation Strategies: Increase conductor size (most common solution), reduce circuit length through optimal routing, use higher system voltage to reduce current, implement power factor correction for reactive loads, install dedicated circuits for high-current equipment, or add voltage regulators where necessary.

Standards Reference: NEC Article 210.19(A) for branch circuits, IEEE 141 for industrial systems, IEC 60364-5-52 for cable sizing.