Our method & sources

Information is only a trust builder if you can check it. Here is exactly how we decide what to publish, how we flag what we are unsure about, and what we refuse to guess.

1. Primary sources only

Every material claim is traced to a primary source: the IET/BSI for standards (by clause reference only — we never reproduce BS 7671 text), GOV.UK and the Approved Documents for legal duties, the DNO and ENA for grid connection, and the vehicle or equipment manufacturer for product behaviour. We record the source and the date we checked it.

2. A four-level confidence taxonomy

Every technical claim is tagged with one of four levels, shown on the page:

• Verified — confirmed against a primary source we can cite.
• Inference — a reasoned engineering conclusion that follows from sourced facts, but is not itself a single quotable line.
• Assumption — a working position stated as such, pending confirmation.
• Not confirmed — we do not yet have a source we trust. We say so rather than guess.

3. The “Not confirmed” gate

Some details depend on documents still being verified — for example, what BS 7671 Amendment 4:2026 changed for V2X and PME, the exact ENA G98/G99 clause locators, or the precise BS 7430:2026 clause numbers. Until those are confirmed against the published standard, the affected detail renders Not confirmed. Where an unconfirmed item is safety-load-bearing — the earthing position, RCD operation in V2L mode, the island earthing arrangement — it blocks the page from being treated as settled rather than publishing with a quiet caveat.

4. Competent-person review

The site’s technical content and every circuit diagram are reviewed for electrical correctness by a competent person (a qualified UK electrician) before a page is rendered on the public site. A page you see marked “reviewed” is public but still carries visible Not-confirmed gates and remains noindex until every publish blocker is closed. Contested approaches — notably floating-V2L-output earthing on a PME supply — are always wrapped in “designed and proven by test by a competent person,” never presented as a recipe.

5. Standards by reference only

BS 7671 and the other standards are copyright. We cite clause and section numbers and gloss them in plain English; we never reproduce the text, tables or figures. To read the wording, obtain the licensed publication. See the standards clause-index for the full map.

6. Review cadence

Every technical page records the BS 7671 edition it was written against and a last-reviewed date. A review is triggered when a new amendment is published, and provisions are verified against the published amendment text before any dependent page is treated as settled.

7. Two audiences, one safety frame

We write for informed homeowners and for qualified electricians at once, but never drop the safety frame: this is education, not an instruction to carry out work, and notifiable work must be designed, installed and tested by a competent person.