Aluminum Service Wire Size Calculator (BS 7671 Standard)
This free calculator helps you select the correct aluminum service wire size for your electrical installation, based on load and voltage, using the BS 7671 standard. Enter your load in watts, select voltage and phase, and instantly get the recommended aluminum cable size for safe and efficient power delivery.
How Aluminum Wire Sizing Works (BS 7671)
- Based on the current-carrying capacity of aluminum cables as per BS 7671 (IET Wiring Regulations).
- Assumes PVC insulation, reference method C (clipped direct), ambient temp 30°C.
- Always consult a qualified electrician and the latest BS 7671 tables for critical installations.
Aluminum Cable Size Chart (BS 7671, up to 630 sqmm)
| Wire Size (sqmm) |
Max Amps (A) |
Typical Load (W) at 230V |
| 6 | 28 | 6,440 |
| 10 | 37 | 8,510 |
| 16 | 48 | 11,040 |
| 25 | 63 | 14,490 |
| 35 | 76 | 17,480 |
| 50 | 92 | 21,160 |
| 70 | 117 | 26,910 |
| 95 | 141 | 32,430 |
| 120 | 162 | 37,260 |
| 150 | 185 | 42,550 |
| 185 | 213 | 48,990 |
| 240 | 247 | 56,810 |
| 300 | 283 | 65,090 |
| 400 | 323 | 74,290 |
| 500 | 367 | 84,410 |
| 630 | 422 | 97,060 |
FAQs
- What is BS 7671? The British Standard for electrical wiring regulations, widely used for safe cable sizing.
- Why use aluminum cables? Aluminum is lighter and more cost-effective for large service cables, but requires larger sizes than copper for the same current.
- What if my load is higher? Use a larger cable size and consult an electrician.
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