Cooker Circuit Voltage Drop Calculator
Check voltage drop compliance for cooker circuits with diversity calculations
Cooker Circuit Quick Facts
- Cooker diversity: First 10A at 100%, remainder at 30%, plus 5A if socket outlet
- Standard cable: 6mm² (7.3 mV/A/m) for most domestic cookers
- Range cookers may need 10mm² cable and 45A MCB
- Cooker control unit should be within 2m of cooker
- Combined oven + hob on single circuit uses diversity calculation
Values from BS 7671 Table 4D1B (PVC copper at 70°C)
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Common Cooker Circuit Scenarios
Standard oven + hob (12kW total)
Diversity: 10A + (42A × 30%) + 5A = 27.6A. 32A with 6mm² at 12m: (7.3 × 32 × 12) ÷ 1000 = 2.80V (1.22%) ✓
Single built-in oven (3kW)
13A load. Can use 2.5mm² but 6mm² preferred. At 10m with 6mm²: (7.3 × 13 × 10) ÷ 1000 = 0.95V (0.41%) ✓
Induction hob only (7.4kW)
32A load (no diversity for single appliance). At 15m with 6mm²: (7.3 × 32 × 15) ÷ 1000 = 3.50V (1.52%) ✓
Range cooker (15kW+)
Diversity: 10A + (55A × 30%) + 5A = 31.5A. 45A MCB, 10mm² recommended. At 15m: (4.4 × 32 × 15) ÷ 1000 = 2.11V (0.92%) ✓
Long run to kitchen extension (25m)
32A with 10mm² (4.4 mV/A/m). At 25m: (4.4 × 32 × 25) ÷ 1000 = 3.52V (1.53%) ✓
Related High-Power Circuits
Installing an electric shower circuit? Similar cable sizing applies but no diversity. For cable current capacity, use our cable sizing calculator. See our main voltage drop calculator for all circuit types.
Cooker Circuit Diversity
Unlike showers, cookers rarely run all elements at full power simultaneously. BS 7671 allows diversity calculation: first 10A at 100%, remainder of rated current at 30%, plus 5A if a socket outlet is included. This typically reduces design current significantly - a 12kW cooker (52A) has design current of only ~28A after diversity.
Cooker Circuit Installation Costs (2024)
Typical UK installation costs. Excludes cooker appliance cost.
| Installation Scenario | Materials | Labour | Total |
|---|---|---|---|
| Simple cooker circuit (10m) | £60-120 | £150-250 | £210-370 |
| Standard install with CCU (15m) | £100-180 | £200-350 | £300-530 |
| Long run or difficult route | £150-280 | £280-450 | £430-730 |
| Range cooker (45A circuit) | £180-320 | £250-400 | £430-720 |
| Separate hob + oven circuits | £150-280 | £350-550 | £500-830 |
Prices as of 2024. Excludes cooker appliance cost.
Why Cooker Diversity Applies
A typical cooker has multiple elements (oven, grill, hob rings) but users rarely run everything at once. Even when cooking a roast dinner, not all hob rings and oven elements operate continuously at full power. Diversity reflects real-world usage patterns and prevents oversizing circuits.
Diversity vs No Diversity
Diversity applies to cookers with multiple elements (oven + hob). For a single appliance like standalone induction hob, no diversity applies - use full rated current. A 7.4kW induction hob = 32A with no reduction. Only apply diversity when combining multiple cooking appliances on one circuit.
Frequently Asked Questions
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