Wire and Cable Sizing Calculator

Calculate maximum cable length for DC, single-phase, two-phase, and three-phase systems while respecting voltage drop limits and insulation temperature ratings. Supports copper/aluminum, parallel conductors, and IEC 60364 & NEC Article 215 compliance. When You Need This Calculation Determining how far a 24V DC solar panel can be from its charge controller Sizing feeders for a 480V three-phase motor located 500 m from the main panel Verifying if a 230V lighting circuit can extend to the end of a long corridor without flickering Designing low-voltage DC distribution in a data center with strict efficiency targets Checking if existing wiring can support a new high-power load without exceeding temperature ratings How Maximum Length Is Determined The tool solves the inverse of Ohm's Law: L_max = (V_drop × A) / (ρ × I × N) Where: L_max : Maximum allowable length (m) V_drop : Allowable voltage drop (V) A : Conductor cross-sectional area (mm²) ρ : Resistivity at operating temperature (Ω·mm²/m) I : Load current (A) N : Number of parallel conductors Note : For AC systems, the formula includes power factor and phase configuration. Temperature & Insulation Rating Conductor temperature affects both resistance and insulation life. This calculator uses temperature-corrected resistivity based on: Insulation Type IEC/CEI NEC Typical Applications PVC 70°C 60–75°C General wiring, indoor circuits XLPE/EPR 90°C 90°C Outdoor, buried, industrial Mineral Insulated 105°C 90°C High-temperature environments, fire-rated THHN/XHHW 90°C 75–90°C Commercial buildings, wet locations Industry-Specific Applications Field Use Case Why It Matters Solar PV String-to-combiner box distance Excessive drop reduces system efficiency and MPPT performance Industrial Motors Feeder from panel to motor Low voltage causes torque reduction and overheating Lighting Systems Long runs in corridors or tunnels 3% max drop ensures consistent brightness and lamp life Data Centers DC power distribution units (PDUs) Efficiency loss directly impacts PUE and cooling load EV Charging From transformer to charging station High currents require careful length planning to avoid voltage sag Reference Standards IEC 60364 : Electrical installations in buildings — limits voltage drop to 3% for lighting, 5% for motors NEC Article 215 : Requires voltage drop not exceed 3% for branch circuits, 5% total from source to outlet IEEE 141 : Recommended practice for electric power distribution in industrial plants UL 486A/B : Wiring device standards including temperature ratings Frequently Asked Questions Why is cable length limited by temperature? Conductors heat up under load. If temperature exceeds insulation rating (e.g., 70°C PVC), it can degrade over time. This calculator ensures both voltage drop and thermal safety are met. Can I use this for underground cables? Yes, but ensure you input the actual operating temperature. Underground cables may run hotter due to soil resistivity and lack of airflow. What is the difference between % and V voltage drop? Percentage drop is relative to supply voltage (e.g., 3% of 230V = 6.9V). Use % for general design; use V when specifying exact tolerance (e.g., motor starter requires ≤10V drop). Does this support multi-core cables? Yes—select 'Multipolar' or specific types like Tripolar, Quadrupolar, etc. The tool assumes all conductors are identical in size, material, and length.

Free online cable power loss calculator. Instantly compute I²R losses, voltage drop, and efficiency for DC/AC systems — supports copper, aluminum, and parallel conductors. How much power is lost as heat in your wires? Enter voltage, load, length, and wire size to instantly calculate I²R losses, voltage drop, and circuit efficiency — compliant with IEC 60364 and NEC standards. Supported Systems & Parameters System Types Direct Current (DC) Single-phase AC Two-phase Three-phase (3-wire or 4-wire) Input Parameters Voltage: Phase-to-neutral (single-phase) or phase-to-phase (polyphase) Load Power: In kW or VA Power Factor: 0–1 (default: 0.8) Wire Size: Cross-sectional area (mm² or AWG) Material: Copper (Cu) or Aluminum (Al) Length: One-way distance (meters) Operating Temperature: Auto-adjusted based on insulation type (PVC, XLPE, etc.) Parallel Conductors: Supported for higher current capacity Output Results Conductor resistance (Ω/km) Total circuit resistance (Ω) Power loss (W or kW) Energy loss (kWh/year, optional) Voltage drop (% and V) Temperature-corrected resistance Compliant with IEC 60364 and NEC Article 310 . Designed for electrical engineers, solar installers, and industrial designers.

Adimissible let-through energy of the cable(K²S²)

Power losses in cables