What Is a Plug-In Microgenerator? The Legal Definition
The UK government uses the term 'plug-in microgenerator' in SI 2026/848. Here's what it means and what qualifies.
The Official Definition
SI 2026 No. 848 defines a "plug-in microgenerator" as a device that:
- Generates electricity from a renewable energy source (in practice, solar photovoltaic panels)
- Connects to the fixed electrical installation of domestic premises via a BS 1363 plug
- Complies with the Interim Product Specification published by DESNZ
The term is deliberately narrow. It doesn't cover wind turbines, generators, battery storage systems, or any device that doesn't meet all three criteria.
Why "Microgenerator"?
The term distinguishes plug-in solar from larger generating installations. In UK energy regulation, "microgeneration" typically refers to systems under 50kW. A plug-in microgenerator is a further subset — limited to 800VA (approximately 800W) and designed for direct consumer installation.
The "plug-in" prefix is key. It means the device connects via a standard BS 1363 plug, not via hardwired connection. This is what makes it different from traditional rooftop solar, which requires an electrician for installation.
What Qualifies?
A device qualifies as a plug-in microgenerator if:
- It generates up to 800VA / 3.5A from solar panels
- It plugs into a BS 1363 socket with a 5A fuse
- It is sold as a complete certified system (panels + inverter + cabling + plug)
- It has no battery storage in the plug circuit
- It includes anti-islanding protection and other safety features required by the IPS v2
What Doesn't Qualify?
The following do not meet the definition of a plug-in microgenerator:
- DIY builds: A Hoymiles or APsystems microinverter bought separately and connected to third-party panels is not a certified system
- Battery systems: The EcoFlow DELTA 2 or similar portable power stations, even with solar input
- Wind turbines: Small wind generators, even if they plug into a 13A socket
- Systems over 800VA: Any generating device exceeding the power limit
- Systems using extension leads: The IPS v2 prohibits extension leads
What About the EcoFlow STREAM?
The EcoFlow STREAM is designed to be the first product certified as a plug-in microgenerator under the IPS v2. While it includes a battery for self-consumption optimisation, the battery is on the DC side and does not feed through the plug circuit — a key distinction.
- 800W dual-panel plug-in solar kit
- 600Wh battery with smart scheduling
- App monitoring with real-time generation data
- Balcony, garden & flat-roof mounts available
Does This Affect G98 DNO Notification?
Yes. You must still notify your Distribution Network Operator within 28 days of installing a plug-in microgenerator. The G98 process is a simple online form — it doesn't require a site visit or electrician.
Why Does the Definition Matter?
The definition matters because only devices meeting it are legal to sell and use from 27 August 2026. Retailers selling non-compliant plug-in solar devices face enforcement action under product safety regulations.
For consumers, it provides clarity: if a kit is certified as a "plug-in microgenerator" under the IPS v2, you can buy and install it with confidence.
Can a plug-in microgenerator be used in commercial premises?
The current definition applies to domestic premises only. Commercial use may be addressed in future revisions.
Is a micro-inverter on its own a plug-in microgenerator?
No. The definition requires a complete system — panels, inverter, cabling, and plug — sold and certified as a single product.
Will the definition expand to include batteries?
Possibly. BSI's full product standard (expected 2027) may broaden the definition to allow integrated battery storage under additional safety requirements.
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