Solar Cable Voltage Drop Calculator
Work out voltage drop on a DC string or single-phase AC run from length, current, conductor size and material — checked against AS/NZS guidance.
- Works out voltage drop on a DC string or single-phase AC run.
- Uses run length, current, conductor size and material as inputs, checked against AS/NZS guidance.
- Returns the drop in volts, the drop as a percentage and a pass or flag against limits.
Voltage drop
0.88V
Drop percentage
0.22%
Assessment
Excellent (≤1%)
For a two-wire DC string or single-phase AC run, voltage drop is:
V drop = (2 × length × current × ρ) ÷ area, where the factor of 2 covers the active and return conductors, and ρ is conductor resistivity (~0.0175 Ω·mm²/m for copper, ~0.0282 for aluminium, near 20 °C).- Drop % =
V drop ÷ system voltage × 100.
AS/NZS 5033caps PV-circuit voltage drop at 3%, and AS/NZS 3000 allows up to 5% total to any point; best practice aims for ≤1% on short runs and ≤2% on longer ones. Real designs use elevated-temperature resistivity and three-phase uses a different factor — this tool is a first check, not a substitute for a licensed electrician's cable sizing.
Estimates only — for guidance, not a quote or engineering specification. Nothing you enter is stored or sent anywhere; the maths runs entirely in your browser.
Frequently asked
- Is this calculator free to use?
- Yes. The voltage drop calculator is free and needs no sign-up. It runs entirely in your browser.
- Is my data stored or sent anywhere?
- No. The calculator runs in your browser and stores nothing. The figures you enter are not saved or sent anywhere.
- Does it support both DC and AC runs?
- Yes. It works out voltage drop for a DC string or a single-phase AC run, and checks the result against AS/NZS guidance as an estimate.
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