What Size Cable Do You Need for a 45 Amp Circuit?
For a 45 amp circuit, use 10mm² copper cable under BS 7671 Table 4D5A, rated at 57A clipped direct. Under NEC, 8 AWG at 75°C is rated for 50A per Table 310.16. This is the standard cable size for large electric cookers and range cookers drawing 9-10kW at 230V single phase.
Quick Reference: Cable Size for 45 Amp Electric Cooker Circuit by Standard
| Standard | Cable Size | Conditions | Reference |
|---|---|---|---|
| BS 7671 | 10mm² | Method C (clipped direct), PVC insulation | Table 4D5A |
| NEC | 8 AWG | 45A circuit, THWN-2, 75°C column | Table 310.16 |
| AS/NZS 3008 | 6mm² | Enclosed in conduit, max 30°C ambient | Table 13 |
| IEC 60364 | 10mm² | Reference method C, PVC insulation | Table B.52.4 |
Values shown are for copper conductors in typical domestic/commercial conditions. Actual size depends on installation method, ambient temperature, and cable length. Use our free cable sizing calculator for your exact scenario.
Typical Applications for a 45 Amp Electric Cooker Circuit
- Electric range cooker
- Large electric cooker
- Commercial oven
- Kiln circuit
Calculate Your Exact Cable Size
These are general guidelines. Your specific installation needs exact calculation accounting for cable route length, installation method, ambient temperature, and cable grouping.
Frequently Asked Questions
Can I use 6mm² for a 45 amp cooker?▼
No. 6mm² cable clipped direct is rated at 47A under BS 7671 — insufficient margin after derating. Use 10mm² which provides 57A capacity. Under AS/NZS 3008 Table 13, 6mm² may suffice in ideal conditions.
What MCB size for a 45 amp cooker circuit?▼
Use a 45A Type B MCB. Standard BS EN 60898 ratings include 40A and 50A — a 45A MCB is available from major manufacturers. Match with 10mm² cable for a compliant installation.
What is the diversity allowance for a cooker circuit?▼
BS 7671 Appendix A allows diversity on cooker circuits: first 10A at 100%, plus 30% of remaining current, plus 5A if a socket is in the cooker control unit. A 12kW cooker at 52A diversifies to approximately 25A.
Is 45 amp enough for a range cooker?▼
Most range cookers draw 35-45A at full load (8-10kW). A 45A circuit with 10mm² cable handles the majority of domestic range cookers. For premium models rated above 10kW, consider a 50A or 63A circuit.
How far can I run 10mm² at 45 amps?▼
At 230V with a 5% voltage drop limit, 10mm² cable can run approximately 18m at 45A. For 6mm², the maximum is only 11m. Most kitchen cable runs are under 15m from the consumer unit.
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