Posted by: @blizzardgreen

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My ideal install would have my battery installed before the CU and have my cu wired to the back up socket.

There are electricians who would be prepared to implement such a strategy...
... but not if the Loads could exceed the 400w available.

You could simply have two consumer units, one of which is supplied by the battery, and the other one with kitchen appliances on it.

I have some circuits which can be changed-over to operate from either the grid supply or the 240v output of a battery system:

Posted by: @transparent

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Posted by: @blizzardgreen

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My ideal install would have my battery installed before the CU and have my cu wired to the back up socket.

There are electricians who would be prepared to implement such a strategy...
... but not if the Loads could exceed the 400w available.

Is it not 3KW?

Posted by: @blizzardgreen

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Is it not 3KW?

As I recall, 3kW is the maximum available from the maintained outlet if you've bought sufficient add-on battery packs.

I'd need to check the specs again to know what level Indevolt will limit the output to if you have just the basic box, with & without a 'charge from the grid' option.

Posted by: @transparent

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Posted by: @blizzardgreen

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Is it not 3KW?

As I recall, 3kW is the maximum available from the maintained outlet if you've bought sufficient add-on battery packs.

I'd need to check the specs again to know what level Indevolt will limit the output to if you have just the basic box, with & without a 'charge from the grid' option.

I had a quick look and they are a little vague.

They say with just the base unit, it's 1 kw. and 3kw with extra batteries, doesn't say how many.

Hopefully it gives half of the battery rating which would be 3 with one extra battery.

Edit to add AI says adding one battery gives 3kw ups.

So take that for exactly what it's worth. 🙂

Posted by: @indevolt-tech

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Standard G98 & BS 7671 Fixed Installation Route:
For users wishing to utilize the 800W grid feed-in / battery storage / peak-shaving capabilities, the PowerFlex 3000 must be installed via a fixed AC connection (e.g., dedicated switched fused spur or AC distribution board circuit) by a qualified electrician under traditional BS 7671 guidelines and registered via standard ENA G98 notification. It cannot rely on the simple plug-in route.

Hi, can you remind me how to enable 3kW feed in when grid tied, do we need base unit plus two batteries? 

Posted by: @indevolt-tech

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2. Standard G98 & BS 7671 Fixed Installation Route:
For users wishing to utilize the 800W grid feed-in / battery storage / peak-shaving capabilities, the PowerFlex 3000 must be installed via a fixed AC connection (e.g., dedicated switched fused spur or AC distribution board circuit) by a qualified electrician under traditional BS 7671 guidelines and registered via standard ENA G98 notification. It cannot rely on the simple plug-in route.

@indevolt-tech  When you say 'dedicated switched fused spur' is that a dedicated spur of a ring main (ie on the load side of the CU) as suggested by your text.

I had understood that microgenerators had to be on an AC distribution board circuit on the supply side, but maybe there is a carve out for sub-800W microgenerators, even those with batteries, that allows them to be installed on a load-side spur.  Please can you quote the actual regulation that you are relying on. 

@jamespa For any battery storage or microgeneration system operating in parallel with the grid (under ENA G98 and BS 7671 Regulation 551.7 regarding low-voltage generating sets): The primary, standard compliance route is a dedicated circuit wired directly to the Consumer Unit (CU), protected by a dedicated bi-directional RCD/RCBO and an adjacent switched isolation point.

Where a "fused connection unit / switched spur" is mentioned in our practical setup discussions, it refers to the local switched isolation point / lockable isolator required near the equipment for safe maintenance, rather than tapping arbitrarily into a heavily loaded general ring main.

Because cable rating, protective device coordination (BS 7671 Section 433/434), and RCD selection (Type A/F/B depending on inverter leakage characteristics) vary per property, the exact circuit design must be determined and signed off by a certified electrician.

@jamespa Hello, to guarantee 100% compliance across all UK Distribution Network Operators (DNOs) and home insurance policies, the primary and most robust compliance route is a dedicated AC circuit wired back to the Consumer Unit (CU), protected by a dedicated bi-directional RCD/RCBO, with a local Switched Fused Spur/Isolator placed next to the unit for safe maintenance.

While an 800W or 3kW inverter connected via a Fused Spur on an existing ring main is technically simple, BS 7671 requires that any parallel generation source does not risk overloading ring circuit conductors (Section 433/434). Therefore, while some qualified electricians may assess a lightly loaded ring circuit and sign it off under Part P, Indevolt officially recommends a dedicated CU circuit to avoid any ambiguity during DNO G98 registration.

Under existing ENA G98 rules, any battery system capable of grid discharge—whether throttled to 800W or operating at full 3.68kW—is classed as a grid-tied energy storage system. There is currently no special exemption under BS 7671 that treats an 800W battery discharge differently from a 3kW battery discharge when connected to home wiring. Both require standard G98 notification and BS 7671 compliance.

To use the Indevolt system legally for grid feed-in / dynamic tariff arbitrage in the UK today:

1. Who: A qualified, Part P-registered electrician.
2. What: Install a dedicated AC circuit (or assess/install a local switched isolator/fused spur) according to BS 7671.
3. Grid Registration: The electrician submits a standard ENA G98 notification (which is Free of Charge) to your local DNO within 28 days of commissioning, using our official G98 Type-Test Certificate (being issued around Aug 20th).

We are currently updating our website (uk.indevolt.com) to include a dedicated "UK Installation & Wiring Pathways Guide" so this exact technical information is completely transparent for all buyers.

Thank you for pushing for this level of detail—this is precisely the clarity the UK market needs. 🙂

@indevolt-tech thanks that's most helpful. 

Hopefully plug in batteries will relatively soon become fully legal! 

Personally I fully understand and support the route government has taken, given the quite extraordinary efforts that the installation industry has gone to in an attempt to block plug in altogether. Nevertheless it's very frustrating as a householder (and doubtless even more frustrating as a manufacturer!).

Posted by: @indevolt-tech

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G99 Standard: Applies strictly to larger installations exceeding 3.68kW per phase, requiring prior DNO approval and complex network studies.

G99 also applies when there is more than one G98 appliance being installed at the same dwelling.

Thus if I were to have a solar-inverter and a storage battery, each capable of export to the grid, then I would complete the online form for G99FT (Fast Track). This is available on the website for your DNO.

This is another minor hurdle which DESNZ needs to address. There are going to be domestic premises which would reasonably like to have two plug-in solar kits, plus an Indevolt battery.

G99 has four Types, which go all the way up to a full power station. Here we are discussing G99 Type-A, which is "below 1MW". See NESO G99 specification document (PDF).

@transparent Thanks for adding this level of accuracy to the thread.