# 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.

**Safety frame.** This is education, not an instruction to carry out work. Work connecting V2L equipment to fixed wiring is safety-critical and may be notifiable under Part P. It must be designed, installed, inspected and tested by a competent person to the current edition of BS 7671. Vehicle manufacturers generally do not sanction back-feeding fixed wiring from V2L outlets; follow manufacturer instructions.

## 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 {#who-signs-off}

- **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

**What governs it:** Approved Document P (England) — who may certify; devolved equivalents elsewhere; BS 7671 (design, installation, verification) and ENA G98/G99 (DNO, where grid-parallel)

**Who may do it:** Designer, installer, inspector/tester, the Part P certifier (scheme or building control) and — where grid-parallel — the DNO. A multi-party competent-person process.

**How compliance is demonstrated:** 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

## FAQ

### 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.

---

_Author: Martin — qualified UK electrician (BEng Mech Eng; vehicle mechanic)._
_Last reviewed: 15 June 2026. Written against: BS 7671:2018 + A4:2026._
_Status: published. General information, not project-specific design advice._
_[How we source this](/methodology) — evidence hierarchy, confidence flags and source policy._

## Sources

1. Approved Document P — Electrical safety (GOV.UK) — https://www.gov.uk/government/publications/electrical-safety-approved-document-p (England; devolved nations differ)
2. IET Code of Practice for EV Charging Equipment Installation (5th ed) — IET (roles in EV/V2X work)