§ Reference layer · Shipping on site daily 2 tools live · more in build

Free tools for working UK electricians.

The reference layer. Useful on site today — and the proof that publishing beats marketing for this audience.

§ 01 · Live · Useful today Free · No account needed
Reference · Fault loop impedance Live

Max Zs Values

A fast lookup of BS 7671 maximum permitted Zs values, Cmin-corrected.

maxzs.co.uk Open Max Zs
Guide · Regulation reader Live

Amendment 4 Guide

Plain-English companion to Amendment 4 of BS 7671. Changed regulations indexed, cross-referenced, annotated.

bs7671amendment4.co.uk Open the guide
§ 02 · Coming soon · In active build Honest · not promised
Ratings lookup In build

Cable CCC & volt drop

Current-carrying capacity tables and volt-drop calcs across installation methods, grouping and ambient temperature.

Inspection schedule In build

EICR observation builder

Canonical BS 7671 observations library with code classification, reg references and remedial costing pattern.

Code finder Planned

BS 7671 regulation finder

Free-text search across all of BS 7671 with context, amendments tracked and a canonical citation format.

Register interest and we'll send the link first.

Register interest Follow the build