Cable Table Pre-check

How to use the Cable Table Pre-check

1. Confirm the circuit uses one of the named Doncaster multicore 70°C thermoplastic copper cable families; twin and earth, aluminium and other constructions are outside this lookup.
2. Choose the circuit arrangement and the exact published reference method confirmed by the electrical designer.
3. Enter the design current and the minimum tabulated capacity already calculated after every applicable design factor.
4. Enter the one-way route length, nominal voltage and the designer's voltage-drop limit.
5. Treat the first table row meeting those two thresholds as a preliminary candidate only, then complete the full electrical design.

Why use this tool

• Uses exact values from one public Doncaster Cables table rather than generic or estimated ratings.
• Separates design current from the corrected tabulated-capacity threshold so omitted derating is visible.
• Fails closed above the published 1–16mm² range instead of silently returning the largest cable.
• Shows the source, edition context and mandatory checks beside the result.

This is not a BS 7671 compliance calculator. It compares a designer-supplied capacity threshold and voltage-drop limit with public manufacturer data for a deliberately narrow cable scope. Before a cable is selected, a competent electrician must verify the protective device, the complete route and installation method, ambient temperature, grouping, thermal insulation, overload and short-circuit protection, fault current, CPC, earth-fault loop impedance, disconnection time, harmonics, special locations and the current manufacturer's data. A table candidate is not authority to purchase, install, energise or certify a circuit.

Part of Builder Tools Calculators — construction tools for UK tradespeople.