Who signs off what — designer, installer, inspector, DNO, scheme provider
A compliant V2L installation is a multi-party process, not one person's job. The designer owns the BS 7671 design (including the contested earthing and the open-PEN measure). The installer builds to that design. The inspector/tester carries out initial verification and issues the certificate. The competent-person scheme or building control provides the Part P sign-off (England; the devolved nations differ). And the DNO must accept the connection where the system can run grid-parallel (G98/G99). No single homeowner step replaces any of these.
In short
- Designer — the BS 7671 design, including the contested earthing and the open-PEN protective measure.
- Installer — builds to the design, by a competent person.
- Inspector / tester — initial verification and the Electrical Installation Certificate.
- Part P sign-off — a competent-person scheme self-certifies, or building control checks (England; Wales/Scotland/NI differ).
- DNO — accepts the connection where the system can run grid-parallel (G98/G99). It is a multi-party process, not DIY.
Where this stops: This maps the responsibilities. It shows that a compliant V2L install is a multi-party competent-person process, not a single DIY task.
The five roles
- Designer — owns the BS 7671 design: the load, the changeover, and the contested earthing (the open-PEN measure, or the TT-island/isolation-transformer decision).
- Installer — installs to the design, as a competent person.
- Inspector / tester — carries out initial verification, proves the protection by test, and issues the Electrical Installation Certificate.
- Part P certifier — a competent-person-scheme electrician self-certifies, or building control checks (England). Wales has its own AD P; Scotland uses a building-warrant model; Northern Ireland has no Part P equivalent and no dedicated electrical-safety Technical Booklet.
- DNO — accepts the connection where the system can run grid-parallel (G98/G99).
No single homeowner step replaces these
Buying a changeover or an adapter does not discharge any of these roles. A safe, lawful V2L install is designed, installed, inspected, certified and (where grid-parallel) DNO-accepted by competent parties.
Jurisdiction matters
The Part P sign-off route is England-specific. Wales operates its own Approved Document P; Scotland uses the Building Standards / building-warrant system with no notifiable/non-notifiable split; Northern Ireland has no Part P equivalent and no dedicated electrical-safety Technical Booklet (Technical Booklet E is fire safety). A UK-wide reader must check the route for their nation.
How this is made and proven compliant
- Approved Document P (England) — who may certify; devolved equivalents elsewhere
- BS 7671 (design, installation, verification) and ENA G98/G99 (DNO, where grid-parallel)
Designer, installer, inspector/tester, the Part P certifier (scheme or building control) and — where grid-parallel — the DNO. A multi-party competent-person process.
- Design recorded; installation to the design; EIC at initial verification
- Part P sign-off (self-certification or building control) in England
- DNO notification/acceptance under G98/G99 where the system can run grid-parallel
Confidence: Inference rolled up across the clauses cited above (the strictest state wins).
Frequently asked questions
Can one electrician do all of it?
Often a competent person designs, installs, inspects and self-certifies under a Part P scheme — but the roles are still distinct, and the DNO step (if grid-parallel) is separate. The point is that each responsibility is met by a competent party.
Do I always need the DNO?
Only where the system can export or run in parallel with the grid (V2G/V2H) — then G98/G99 applies. A true islanded V2L (changeover, no export) is generally treated as a load and does not engage the DNO regime.
Is Part P the same across the UK?
No. Part P / Approved Document P is England. Wales has its own AD P; Scotland uses a building-warrant model; Northern Ireland has no Part P equivalent and no dedicated electrical-safety Technical Booklet. Check the route for your nation.
- Last reviewed
- 15 June 2026
- Written against
- BS 7671:2018 + A4:2026
- Reviewed by
- Martin (qualified UK electrician)
- Next review due
- 14 December 2026
General information, not project-specific design advice. Standards are cited by reference only and never reproduced. How we source this.
References & sources (2)
- Approved Document P — Electrical safety (GOV.UK) — England; devolved nations differ
- IET Code of Practice for EV Charging Equipment Installation (5th ed) — IET — roles in EV/V2X work