Consuel ESS sans réinjection

Been down a similar rabbit hole recently, and thought it was worth raising here because I don't see it discussed much in a UK context.

I'm in the process of documenting my garden office setup for compliance purposes — not grid-tied in the traditional sense, but I do have a Victron Multiplus-II and a Fogstar Drift lithium bank, and I wanted to make sure everything was above board before my electrician signs it off.

The French Consuel process (their equivalent of our NAPIT/NICEIC certification route) apparently requires specific technical dossiers for ESS installations with no grid export — essentially proving the system is genuinely zero-export rather than just claiming it. Got me thinking: are we being rigorous enough about this on the UK side?

With G98/G99 notifications and the DNO paperwork, it feels like there's a process, but I've spoken to two different sparks who gave me completely different answers about what's actually required for a non-export ESS in a garden building. One said it was straightforward permitted development territory, the other said I needed a full G99 application regardless of the battery-only setup.

Has anyone here gone through a formal compliance route for an off-grid or genuinely non-export ESS — particularly in a garden office, cabin, or similar outbuilding? Curious whether anyone's had an inspector actually scrutinise the Victron ESS assistant config or the CT clamp wiring to verify zero-export.

Would love to know what documentation others have pulled together — especially if your setup is similar (Multiplus-II, no solar export, just load shifting from grid).

Hey @WattHelen, interesting one to raise here. The Consuel certification is very much a French regulatory thing, so it doesn't translate directly to UK installations - we're working under BS 7671 and G98/G99 notification requirements instead.

That said, the underlying concept of a zero-export or "sans réinjection" configuration is absolutely relevant for UK garden office setups, particularly if you want to avoid the DNO notification paperwork entirely by keeping generation self-contained.

Most of us achieve this through the inverter's export limitation settings rather than any formal certification process. Worth checking whether your inverter has a proper anti-islanding function and that your setup meets the relevant parts of BS EN 62109.

What inverter are you running? That'll likely determine how straightforward the zero-export configuration actually is in practice.

Yeah this is a France-specific cert so a bit niche for this forum tbh — but worth knowing about if you're buying secondhand kit off French marketplaces, since some Victron gear over there gets locked into ESS configs you can't easily undo without a dealer.

For UK garden office stuff you're generally dealing with G98/G99 if you're grid-tied, or just... nothing formal if you're fully off-grid like mine is. No injection, no paperwork, job done.

The "sans réinjection" bit basically means zero export — which is what most of us are doing anyway with a Multiplus and an ESS assistant set to 0W export. Just not called that here.

What inverter are you running @WattHelen? Might be relevant to whether any of this actually applies to your setup.

@WattHelen worth flagging that even if you're sourcing kit that has Consuel ESS certification from French sellers (secondhand Victron Multiplus units being the obvious one), the underlying G98/G99 compliance question in the UK is entirely separate. Consuel approval doesn't map across to DNO notification requirements here.

For a garden office running as a genuine standalone backup system with no grid export whatsoever, you're arguably in simpler territory anyway — if your system is genuinely isolated from the grid during operation, G98 doesn't apply. The critical thing is ensuring your transfer switch arrangement actually prevents any backfeed pathway, which is where a lot of DIY installs quietly fall over.

My own setup uses a Victron MultiPlus in ESS with a hardwired no-export configuration. Had an electrician verify the isolation before commissioning. That paper trail matters if you ever need to deal with your DNO.

@WattHelen to add a practical angle — if you're documenting a UK garden office setup, your relevant compliance path is more about G98/G99 (if you ever grid-tie) and building regs/permitted development. For a purely off-grid setup like mine, neither applies directly but I still keep a paper trail of equipment specs, wiring diagrams, and battery datasheets in case of insurance queries.

On the secondhand Victron kit point @SolarJake raised — worth cross-referencing serial numbers on Victron's own portal. Tells you firmware history and whether it's been registered to another VRM account, which hints at its past life regardless of what certifications the seller claims.

@WattHelen bought a Victron Multiplus off a French bloke on eBay once — turned up with a sticker I couldn't read and settings I couldn't explain, which is basically the off-grid experience in a nutshell.