# V2L vs V2H vs V2G — definitions and boundaries

> **V2L** (vehicle-to-load) is the car acting as a standalone AC inverter, feeding portable appliances through a socket or adapter — there is no grid handshake, so it sits outside the ISO 15118 communication standard and outside the DNO's G98/G99 connection regime. **V2H** (vehicle-to-home) is a communicating bidirectional charger feeding the home's wiring — that is ISO 15118-20 territory. **V2G** (vehicle-to-grid) adds bidirectional export running in **parallel** with the grid, which is DNO-notifiable under ENA G98/G99. The line is simple: a plain V2L socket is neither ISO 15118 nor G98/G99 — until its output is wired into the fixed installation (a changeover into the consumer unit) or it runs in parallel with the grid.

## In short

- **V2L** — the car as a standalone AC inverter feeding portable loads via the Type 2 inlet/adapter. **No grid handshake.** Outside ISO 15118 and outside G98/G99.
- **V2H** — a communicating **bidirectional charger** feeding the home's fixed wiring (typically via a changeover). The comms layer is **ISO 15118-20** territory.
- **V2G** — bidirectional **export in parallel** with the grid. **DNO-notifiable** under ENA G98/G99.
- The boundary: a plain V2L socket is not ISO 15118 and not G98/G99 **until** its output is wired into fixed installation (changeover into the consumer unit) or runs in parallel with the grid.
- Powering fixed wiring from any of these is competent-person work to the current edition of BS 7671; the vehicle manufacturer generally does not sanction back-feeding fixed wiring from a V2L outlet.

**Where this stops:** This is a definitions page — it draws the lines between the three technologies. It is not a wiring recipe; any arrangement that feeds a home's fixed wiring is for a competent person to design, install and test.

## Three names, three very different things {#v2l-vs-v2h-vs-v2g}

V2L, V2H and V2G all describe energy flowing **out** of an electric vehicle, but they are not interchangeable. They differ in what the car talks to, what it feeds, and which rulebook applies. Getting the term right is not pedantry — it decides whether you are looking at a portable appliance, a notifiable fixed-wiring installation, or a grid connection that the network operator must be told about.

- **V2L (vehicle-to-load)** — the car acts as a standalone AC inverter (an AC generator), feeding portable appliances plugged straight into a socket or a Type 2 adapter. No grid handshake.
- **V2H (vehicle-to-home)** — a communicating bidirectional charger feeds the home's fixed wiring, typically through a changeover, usually during an outage or for load-shifting.
- **V2G (vehicle-to-grid)** — a bidirectional charger exports energy back to the public grid, running in parallel with it, to provide grid services or energy arbitrage.

> **The one-line test** — Are you plugging an appliance into the car (V2L), wiring the car into your home (V2H), or selling power back to the grid (V2G)? Each answer puts you under a different set of standards.

## V2L — the car as a standalone inverter

In V2L the vehicle's onboard power electronics run in reverse: the inverter turns the traction battery's DC into ordinary 230 V AC and delivers it through a built-in socket or an adapter that plugs into the car's Type 2 inlet. You plug appliances directly in. Critically, there is **no high-level digital handshake with charging equipment or the grid** — the car is simply acting as a generator. Output is typically in the 1.8–3.6 kW range on European models, though some vehicles export far more.

Because a V2L adapter draws power *out* of the vehicle rather than charging it, V2L sits **outside** the IEC 61851 charging-mode framework (Modes 1–4) and outside its control-pilot path — a V2L outlet is a separate vehicle-side AC output, not a control-pilot-mediated charging session.

> **-1 (charging Modes 1–4)** (BS EN IEC 61851, confidence: inference) — The four conductive charging modes the whole EV-supply vocabulary rests on. V2L sits outside these modes because it takes power out of the vehicle rather than charging it — so a V2L backup bypasses the control-pilot path that protects a normal charging session. _Reference only; standard text not reproduced._

> **Confidence: inference** — The exact internal architecture of a V2L adapter (DC out then inverted in the adapter, versus inversion inside the vehicle) varies by manufacturer. (The V2L guide states the architecture is not assumed and varies by design; confirm against the specific model's documentation. It does not change the boundary point — either way there is no ISO 15118 grid handshake.)

## V2H — a communicating bidirectional charger feeding the home

V2H is a different animal. Here a dedicated **bidirectional charger** is hardwired into the home and feeds the fixed wiring — typically through a transfer/changeover arrangement so the house can run from the car during an outage or on a schedule. This is not a dumb socket: it requires a managed, communicating discharge, which is where the ISO 15118 series — and specifically **Part 20** — comes in. V2H readiness depends on **both** ends supporting Part 20, not just the car having a V2L socket.

> **Part 20 (-20:2022)** (BS EN ISO 15118, confidence: inference) — Bidirectional power transfer — the only part of ISO 15118 that specifies session control for power flowing out of the vehicle. It is the communication backbone of true V2H/V2G, and it is exactly what a plain V2L socket does NOT use. _Reference only; standard text not reproduced._

On the equipment side, the DC bidirectional charging work in BS EN IEC 61851 (-23:2023 adds bidirectional power transfer for DC supply equipment; -24:2024 extends digital communication to discharging) is the technical foundation that makes safe, controlled V2H/V2G operation possible — again, distinct from a plain AC V2L socket with no negotiation.

> **-23:2023 / -24:2024 (bidirectional / discharge)** (BS EN IEC 61851, confidence: inference) — The 2nd editions formally address energy flowing out of the vehicle through DC equipment, with digital communication extended to discharging — the regulated, grid-aware pathway behind V2H/V2G. _Reference only; standard text not reproduced._

## V2G — bidirectional export in parallel with the grid

V2G goes one step further than V2H: the bidirectional charger doesn't just feed the home in isolation, it **exports** energy back to the public network, running in **parallel** with the grid for grid services or arbitrage. The moment a source can run in parallel with, or export to, the public supply, it engages the DNO's connection regime — **ENA EREC G98/G99**. G98 is the lighter, type-tested microgeneration route (within the small-generator threshold); G99 covers larger or island-capable installations, and is recorded as expressly treating a bidirectional EV as electricity storage subject to G99.

> **G99 — V2G EV as electricity storage (locator Not confirmed)** (ENA EREC G99, confidence: inference) — G99 Issue 2 is recorded as naming the bidirectional EV and classifying it as electricity storage subject to G99 — the hook that makes grid-parallel V2G DNO-notifiable. Exact section/clause locators are Not confirmed pending the official ENA PDF. _Reference only; standard text not reproduced._

**Figure: Grid-parallel vs islanded — the DNO-notification line.** Running a source in parallel with the grid engages ENA G98/G99 (DNO notification); a true islanded changeover that never connects the two together is generally treated as a load, outside G98/G99.

_Two arrangements. On the left, the grid and the EV/source are connected together (in parallel) — this engages ENA Engineering Recommendations G98/G99, so the DNO must be notified. On the right, a break-before-make changeover switch connects the load to either the grid OR the EV/source, never both together (islanded) — a source that can never run in parallel or export is generally treated as a load and sits outside G98/G99. Whether a given changeover genuinely prevents parallel operation is a design-and-test matter for the competent person and the DNO. The exact G98/G99 clause locators are Not confirmed pending the official PDFs._

> **Not confirmed (safety-critical):** The exact ENA G98 Issue 2 / G99 Issue 2 clause and section locators (the G98 microgeneration per-phase threshold wording, the G99 V2G-as-storage classification, and the V2L load carve-out) are Not confirmed pending the official ENA PDFs — they are cited here as inference, not as precise locators.

## Where the boundary actually sits

Here is the line that matters, stated plainly: **a plain V2L socket is not ISO 15118 and not G98/G99.** It is the car acting as a standalone inverter for portable loads. It only crosses into the regulated world in two situations:

1. **Wired into fixed installation** — the instant a V2L output is taken into the home's fixed wiring (a changeover into the consumer unit, an inlet circuit, a sub-board), it becomes a BS 7671 installation matter and normally notifiable work — even though the car-side comms are still nothing like ISO 15118.
2. **Run in parallel with the grid** — the instant the arrangement can export to, or run in parallel with, the public supply, it engages the DNO regime (G98/G99). A true islanded changeover that physically cannot connect the two together is generally treated as a load and sits outside G98/G99 — but whether a given changeover genuinely prevents parallel operation is a design-and-test matter for the competent person and the DNO.

> **§722** (BS 7671, confidence: inference) — Electric vehicle charging installations — the special-location section. A car's standalone V2L socket sits outside §722 until its output is wired into the consumer unit, at which point the fixed-installation rules engage. _Reference only; standard text not reproduced._

> **Two different boundaries — don't conflate them** — ISO 15118 marks where V2L ends and *communicating* V2H/V2G begins (the comms boundary). G98/G99 marks where you start running in *parallel with the grid* (the connection boundary). A V2H island can be communicating (ISO 15118-20) without exporting, and so without engaging G98/G99 — the two lines are not the same.

## Why the distinction is practical, not academic

Marketing blurs these terms — a high-output V2L truck feeding a home integration system starts to look like V2H, and 'bidirectional' is used loosely. But the rulebooks are sharply different: a portable appliance under V2L, a notifiable fixed-wiring installation under V2H, and a DNO-notified grid connection under V2G. Confusing them is how people end up assuming a car with a V2L socket is 'V2H-ready' (it usually is not — that needs ISO 15118-20 at both ends and a bidirectional charger) or assuming an islanded backup needs a grid agreement (it generally does not, provided it truly cannot run in parallel).

> **Not confirmed (safety-critical):** Whether BS 7671 A4:2026 made any V2X/PME/V2H-specific change to §722 is Not confirmed — the public IET/BSI change material checked here does not identify a §722 / V2X / PME / open-PEN change in A4:2026, and existing §722 / PME/open-PEN material appears to carry forward from earlier amendments, subject to licensed-text confirmation. Do not assert an A4-specific V2X change until confirmed against the published standard.

### How this is made and proven compliant

**What governs it:** BS EN ISO 15118 (esp. Part 20) — the communication interface that marks where V2L ends and communicating V2H/V2G begins; BS EN IEC 61851 (-1 Modes 1–4; -23/-24 DC bidirectional) — the vehicle/charger interface side; ENA EREC G98 / G99 — the DNO connection regime engaged when a source runs in parallel with the grid; BS 7671 §722 and §551 — the fixed-installation side once a V2L output is wired into the consumer unit

**Who may do it:** Defining the terms is education. Acting on them — wiring a V2L output into fixed installation, or installing a communicating bidirectional charger — is design, installation, inspection and testing by a competent person, and is normally notifiable under Part P (England; Wales/Scotland/NI differ). Grid-parallel operation also requires the appropriate DNO notification.

**How compliance is demonstrated:** Establish which technology you actually have: standalone socket/adapter (V2L), communicating bidirectional charger feeding the home (V2H), or grid-parallel export (V2G); For V2H/V2G: confirm BOTH ends speak ISO 15118-20 — a car with a V2L socket is not, on its own, V2H-ready; For any grid-parallel arrangement: confirm the DNO notification route (G98 vs G99) with the competent person and the network operator; For an islanded V2L changeover: prove by test that the changeover genuinely prevents parallel operation, keeping it outside G98/G99

## FAQ

### Is V2L the same as ISO 15118 / 'Plug and Charge'?

No. A plain V2L socket is the car acting as a standalone inverter, with **no high-level digital handshake** — it does not use ISO 15118. ISO 15118 (especially `Part 20`) becomes relevant only for a communicating bidirectional charger feeding the consumer unit, i.e. true V2H/V2G.

### Does my car having a V2L socket mean it can do V2H?

Not on its own. V2H needs a communicating **bidirectional charger** and ISO 15118-20 support at **both** ends (car and charger), plus a designed changeover into the home. A V2L socket is a standalone AC outlet — it is not, by itself, a V2H system.

### Do I have to notify the DNO to use V2L for backup?

Generally not, **if** the V2L arrangement is truly islanded — physically separated by a changeover so it cannot run in parallel with or export to the grid. The DNO regime (ENA G98/G99) is engaged by **parallel/export** operation, which is V2G territory. Whether a given changeover genuinely prevents parallel operation is a design-and-test matter for the competent person and the DNO. *(The exact ENA locators are Not confirmed pending the official PDF.)*

### When does a V2L setup stop being 'just a socket' and become regulated?

Two triggers. First, the moment its output is wired into **fixed installation** (a changeover into the consumer unit, an inlet circuit) — it becomes BS 7671 work, normally notifiable under Part P. Second, the moment it can run in **parallel** with the grid — it engages G98/G99. Either trigger moves it out of the 'plug-in appliance' world.

### What's the difference between V2H and V2G in one sentence?

V2H feeds **your home** (typically islanded, during an outage or for load-shifting); V2G feeds **the grid** by exporting in parallel with it. V2H need not engage G98/G99 if it never parallels; V2G always does.

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_Author: Martin — qualified UK electrician (BEng Mech Eng; vehicle mechanic)._
_Last reviewed: 14 June 2026. Written against: BS 7671:2018 + A4:2026._
_Status: reviewed. General information, not project-specific design advice._
_[How we source this](/methodology) — evidence hierarchy, confidence flags and source policy._

## Sources

1. BS EN ISO 15118 series (key part -20:2022, UK publication 30 June 2025) — Road vehicles: Vehicle-to-grid communication interface (BSI/ISO) — https://knowledge.bsigroup.com/products/road-vehicles-vehicle-to-grid-communication-interface-2nd-generation-network-layer-and-application-layer-requirements (cited by part/edition number only; standard text not reproduced)
2. BS EN IEC 61851 series (-1:2019; -23:2023; -24:2024) — Electric vehicle conductive charging system (BSI/IEC) — https://knowledge.bsigroup.com/products/electric-vehicle-conductive-charging-system-general-requirements-5 (cited by part/edition number only; standard text not reproduced)
3. ENA EREC G98 Issue 2 / G99 Issue 2 (10 Mar 2025) — Connection of generation/storage to the distribution network (Energy Networks Association) — https://www.energynetworks.org/industry/connecting-to-the-networks/connecting-generation-to-the-electricity-networks (exact clause/section locators Not confirmed pending the official ENA PDF)
4. BS 7671:2018+A4:2026 §722 — Requirements for Electrical Installations (IET/BSI) — https://electrical.theiet.org/bs-7671-18th-edition-wiring-regulations/about-bs-7671/ (cited by clause only; standard text not reproduced)
5. V2L Workshop V2L guide and standards cards (internal) — definitions, boundary points and confidence flags