Drawing tool

Wiring diagram generator

Choose a circuit type and a consumer unit size. The tool draws the board schedule and the circuit layout — every conductor labelled with its size, the protective device rating, and the RCD requirement that applies. Download either drawing as an SVG to drop into a quote, a spec or a training sheet.

Choose the circuit

Circuit typeConsumer unit sizeBoard protectionEarthing arrangementSockets on the run: 6

Conductor schedule

Protective device: 32 A Type B RCBO
Line / neutral: 2.5 mm²
Protective conductor: 1.5 mm²
Cable: Flat twin & earth (6242Y)
RCD: 30 mA RCD protection required — Reg 411.3.3 (socket outlets ≤ 32 A).
Length / load: Both legs together should not exceed about 100 m of 2.5 mm² for voltage drop and r1+r2.

Guidance only

These drawings show the common domestic arrangement. Conductor sizes must be confirmed by calculation for the actual installation method, grouping, insulation, ambient temperature, length, Zs and voltage drop against BS 7671:2018+A4:2026 (previous A2:2022+A3:2024 version also current until 15 October 2026). All Cabling Limited accepts no liability for any loss, damage, injury or non-compliance arising from use of this tool.

Run the numbers on the circuit design tool before you install.

Board layout

A typical schedule for a 10-way board with the selected circuit highlighted on way 1. An RCBO per way keeps a fault on one circuit from tripping the rest of the house.

Circuit layout & wire sizes

Socket outlets — 32 A ring final — 2.5 mm² / 1.5 mm² cpc on a 32 A device.

Points to watch on this circuit

Both legs must return to the same terminal at the board — test r1, rn and r2 end to end before energising.
One unfused spur per point: a single or twin socket only, taken from a socket on the ring or a junction box in the ring.
For the supported 32 A ring arrangement, each conductor needs an effective current-carrying capacity of at least 20 A after applicable correction factors (Reg 433.1.204); check load distribution and installation conditions.