Electrical Voltage Drop & Wire Gauge
Calculate AS/NZS 3000 voltage drop and cable sizing.
Last reviewed by the myCalculator Editorial Team
Input Parameters
Calculation Results
Next: related Engineering calculators
Concrete Volume & Bag Calculator
Estimate concrete volume for house slabs, footings, steps, and posts.
Topographic Map Scale Calculator
Calculate real-world ground distances from topographic maps using standard scales (1:25,000, 1:50,000, 1:100,000).
Contour Slope & Gradient Calculator
Determine terrain steepness, gradient percentage, and slope angle from topographic map contour intervals and horizontal distance.
Formula & How Electrical Voltage Drop & Wire Gauge Works
Voltage drop in a cable is the voltage lost along its length. For a single-phase circuit it is Vd = 2 × L × I × ρ ÷ A, where L is the one-way length in metres, I the current in amps, ρ the resistivity (about 0.0175 Ω·mm²/m for copper) and A the conductor area in mm². A 30 m run carrying 20 A in 2.5 mm² copper drops 2 × 30 × 20 × 0.0175 ÷ 2.5 = 8.4 V, which is 3.65% of 230 V. AS/NZS 3000 sets a limit of 5% from the point of supply to the load, so that run complies, but a longer run or a heavier load might need a larger cable. A licensed electrician must design and install wiring.
- Enter Supply Voltage (V): Input your target parameter value.
- Enter Load Current (Amps): Input your target parameter value.
- Enter One-Way Cable Run (meters): Input your target parameter value.
- Enter Conductor Size (mm²): Input your target parameter value.
- Apply Formula: Calculate using
Vdrop = (2 × L × I × ρ) / Area. - Review Results: View exact computed answers, metrics, and worked mathematical proofs.
Need this calculator for your blog, publication, or client portal?
Get pre-formatted embed codes, Markdown citations for forums (Reddit/Whirlpool), or HTML anchor tags free.
Cite this Calculator
Are you using our calculation results for a university assignment, research paper, or academic report? Use the auto-generated citations below to accurately reference this tool in your bibliography.
MyCalculator.com.au. (2026). Electrical Voltage Drop & Wire Gauge. Retrieved October 24, 2026, from https://www.mycalculator.com.au/calculators/engineering/voltage-drop
MyCalculator.com.au. (2026) 'Electrical Voltage Drop & Wire Gauge'. Available at: https://www.mycalculator.com.au/calculators/engineering/voltage-drop (Accessed: 24 October 2026).
Frequently Asked Questions (FAQs)
What cable size is standard for 10A power points?
2.5 mm² copper cable is standard for Australian 10A power circuits.
Embed Electrical Voltage Drop & Wire Gauge on Your Site
Offer your readers, students, or clients interactive calculations. Fast, responsive, and 100% free with no login required.
Widget Customizer
Recommended for publishers & educational portals to provide source citation.
Authoritative Standards & Verified Reference Citations
Calculations and mathematical logic on this page are grounded in published statutory rules, regulatory standards, and official government data published by the following bodies:
Australian Standards including AS/NZS 3000 (Wiring Rules), AS 3600 (Concrete Structures), and AS 4100 (Steel Structures).
Accreditation and technical guidelines for civil, structural, mechanical, and electrical engineering.
Dedicated Australian home loans, borrowing capacity, mortgage repayments & refinance modeling.