BS 7671 design tool
Cable size calculator
Calculate corrected current-carrying capacity (Iz), verify the Ib ≤ In ≤ Iz device chain, voltage drop and adiabatic CPC size. Covers single-phase and three-phase circuits.
For homeowners — pick your appliance, answer 3 questions, get plain English advice.
1What are you wiring?
Select the appliance or circuit you need to size a cable for.
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