IEC 60364-5-52
NEC 310.16
GB 16895
Voltage-drop check
Cable size calculator
Professional wire cross-section sizing by current or power — IEC, NEC (USA) and GB (China) standards, with voltage-drop check and ready-to-order cable options.
Free, ready-to-embed cable calculator — pick a style and your brand color, copy the snippet, done. It loads in an iframe, so it never clashes with your page styles.
Style and color apply to the tool right below — what you see is what the embedded widget looks like.
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Recommended conductor
Enter a value to see the recommendation.
Installation method
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Cable options
Nearest standard size that carries the load with your installation conditions and stays within the voltage-drop limit.
| Size | Ampacity | V-drop | Status |
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How the sizing works
1 · Load current
From power the current is Ib = P / (V · cos φ) for single-phase, or Ib = P / (√3 · V · cos φ) for three-phase. Enter current directly to skip this step.
2 · Correction factors
The table ampacity of every size is corrected for installation method, ambient temperature and grouping. A conductor is valid only when its corrected ampacity is at least the design current.
3 · Voltage drop
Drop is ΔU = k · I · L · ρ / S (k = 2 single-phase, √3 three-phase; ρ = 0.0175 Ω·mm²/m copper, 0.0282 aluminium). If a size exceeds your limit it is rejected even when its ampacity is enough.
4 · Recommendation
The smallest size passing both checks is recommended; nearby sizes are listed as alternatives, with the closest equivalent shown in the other standards.
Important
This tool gives a fast engineering estimate for typical PVC/XLPE insulated cables. Correction factors are simplified. Final conductor and protective-device selection must follow the full local wiring code (IEC 60364, NEC/NFPA 70, GB 50054, etc.) and, where required, be approved by a qualified electrical engineer.