Cable Size & Voltage Drop Calculator
Quickly calculate the correct cable size for both copper and aluminum cables to ensure safe current carrying capacity and meet voltage drop requirements. Suitable for electrical engineering design, construction, and maintenance.
Accurate Current Ratings
Based on IEC standards for PVC-insulated cables, providing reliable current carrying capacity data for safe electrical installations.
Precise Voltage Drop
Calculate voltage drop for both single-phase and three-phase systems to ensure compliance with electrical code requirements (≤3% drop).
Material Selection
Compare copper and aluminum cable options to find the most suitable and cost-effective solution for your specific electrical project needs.
Input Parameters
Calculation Results
Recommended Cable Size
- mm²
Voltage Drop
- V
Voltage Drop %
- %
Cable Current Carrying Capacity Table
Frequently Asked Questions
According to NEC 2023 Article 310 and IEC 60364-5-52, cable size selection depends on load current (NEC Table 310.16), ambient temperature derating factors, installation method (conduit, tray, direct burial), insulation type (THHN, THWN, XHHW), number of current-carrying conductors (derating factors in NEC Table 310.15(B)(3)(a)), and voltage drop limitations. Our calculator follows these standards to ensure code-compliant results.
NEC 210.19(A)(1) FPN No. 4 and 215.2(A)(4) FPN No. 2 recommend a maximum 3% voltage drop for branch circuits and 5% for feeder circuits combined with branch circuits. IEC 60364-5-52:2011 similarly suggests 3% for lighting and 5% for other loads. Our calculator uses these guidelines to ensure optimal electrical system performance.
For motor circuits, NEMA MG 1-2020 and NEC Article 430 require cables to be sized based on 125% of the motor full-load current (FLA) as listed in NEC Table 430.248 or 430.250. Our calculator includes specific motor circuit sizing options that apply these factors automatically, ensuring compliance with both safety and performance requirements.
Our AWG to mm² conversion follows ASTM B258-18 and IEC 60228 standards, providing precise cross-sectional area calculations. For example, 10 AWG converts to 5.26 mm², and 4/0 AWG converts to 107.2 mm². This level of accuracy ensures compatibility between American and international cable sizing systems, crucial for global projects and equipment specifications.
Solar PV system cables must comply with NEC Article 690 and IEC 60364-7-712. Key considerations include DC voltage rating (PV wire or USE-2 insulation), temperature cycling resistance, and derating for high ambient temperatures in roof-mounted installations. Our calculator includes specific settings for PV systems, accounting for these unique requirements and the higher voltage drop tolerance often allowed for DC circuits.
Three-phase systems use a formula involving √3 (1.732) to account for balanced loads, allowing smaller conductors for the same power compared to single-phase. For example, a 100A three-phase load at 480V carries approximately 83kW, while a single-phase 100A load at 240V carries 24kW. Our calculator automatically applies the correct formulas based on your selection, ensuring accurate sizing for both residential (typically single-phase) and commercial/industrial (often three-phase) applications.
Cable Application Scenarios & System Types
Residential
Home electrical wiring, lighting, outlets, appliances, HVAC systems, and EV charging stations (NEC 210, 215).
Commercial
Office buildings, retail spaces, restaurants, and medium-load commercial systems (NEC 300, 310).
Industrial
Factories, manufacturing facilities, and heavy machinery with high-power three-phase distribution (NEC 400, 430).
Motor Circuits
Electric motor installations, including sizing for starting currents per NEMA MG 1 and NEC Article 430.
Solar PV
Solar panel installations, DC wiring, and inverter connections (NEC 690, IEC 60364-7-712).
EV Charging
Residential and commercial EV charging stations, Level 1, 2, and DC fast charging (NEC 625).
Understanding Cable Selection for Electrical Systems
Proper cable selection is critical for electrical safety, system efficiency, and compliance with regulatory standards like NEC 2023 (National Electrical Code) and IEC 60364 (International Electrotechnical Commission). Our calculator follows guidelines from NEC Table 310.15(B)(16) and IEC 60364-5-52 for current carrying capacity calculations.
According to electrical codes, voltage drop should generally not exceed 3% for branch circuits (NEC 210.19(A)) and 5% for feeder circuits (NEC 215.2(A)(4)). This tool helps ensure your installation meets these requirements while preventing overheating and potential fire hazards.
For specific applications like motor cable sizing, our calculator accounts for starting currents and duty cycles as specified in NEMA MG 1 and IEC 60034 standards. The AWG to mm² conversion feature supports both imperial and metric measurement systems.
Ideal for electrical engineers, contractors, and DIY enthusiasts working on residential, commercial, industrial, and renewable energy projects like solar power systems. Always consult a licensed electrician for complex installations.
AWG to mm² Conversion Table
| AWG Size | mm² | Approx. Diameter (mm) | Typical Current Rating (A) |
|---|---|---|---|
| 4/0 (0000) | 107.2 | 11.68 | 230-320 |
| 3/0 (000) | 85.0 | 10.40 | 195-270 |
| 2/0 (00) | 67.4 | 9.26 | 165-230 |
| 1/0 (0) | 53.5 | 8.25 | 140-195 |
| 1 | 42.4 | 7.35 | 120-170 |
| 2 | 33.6 | 6.54 | 100-145 |
| 4 | 21.1 | 5.19 | 70-100 |
| 6 | 13.3 | 4.11 | 50-70 |
| 8 | 8.37 | 3.26 | 35-50 |
| 10 | 5.26 | 2.59 | 25-35 |
| 12 | 3.31 | 2.05 | 20-25 |
| 14 | 2.08 | 1.63 | 15-20 |
Values based on NEC 2023 and IEC 60228 standards. Current ratings are approximate for typical installations and may vary based on insulation type, ambient temperature, and installation method.