Direct answer: A compliant kit is half the job. The socket, the circuit protection and the plug all have requirements, and the specification is explicit about what they are.
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Plug-in Solar Safety: the RCD, RCBO and Socket Rules That Actually Apply
Buying a kit from the register is the first condition of a safe installation, not the last. The specification that defines a compliant kit also defines what the installation it plugs into has to look like — and those requirements are written as instructions the manufacturer must give you, which makes them checkable before you buy.
The kit itself: three limits that matter
- 800 VA of apparent power and 3.5 A of current into the installation, maximum. That ceiling is in the specification (clause 4.1) and, since 27 August 2026, in law as part of the definition of a plug-in microgenerator.
- 2,000 W of panel capacity, across no more than four modules.
- 5 mA: the maximum smooth DC residual current the device may put into the mains under normal and fault conditions (clause 5.7). This is the number that decides whether your existing protection still works.
Clause 5.7 also requires that the device does not adversely affect upstream residual current devices. That is the technical reason the RCD question is not a formality: a solar inverter feeding the mains can blind certain types of RCD to a fault.
Which RCD, and which one is wrong
Electrical Safety First's guidance on plug-in solar panels recommends that the circuit used for plug-in solar is protected by at least a Type A bidirectional RCD, and warns that homes with Type AC RCDs should not use plug-in solar on those circuits without upgrading the protection first.
The practical check is a look inside the consumer unit. Type AC devices are common in installations of a certain age and are marked "AC" on the device. Type A devices are marked "A". If the circuit you intend to use sits behind a Type AC RCD, the honest answer is that it needs an electrician before it gets a kit.
RCBOs and older fuse boards
The specification requires manufacturers to advise buyers to check that the electrical installation is equipped with modern residual current protection (RCBO) and is in good condition, and to state that where the installation uses older fuse protection and does not incorporate RCBOs, it must be checked — and where necessary upgraded — by a professional electrician.
An RCBO combines overcurrent and residual current protection in one device. A rewireable fuse board with no RCD protection at all is not a suitable host for a grid-connected generator, whatever the marketing copy says.
One kit, one circuit, and the household limit
The specification permits one plug-in solar device per final circuit, so that the current through the connection to the consumer unit stays within safe levels. The network requirements go further: Engineering Recommendation G98, as currently published, restricts this to one device per household.
In practice: do not buy two kits intending to run them on different sockets and assume you are within the rules. You are not.
Plugs, adaptors and extension leads
A compliant kit ends in a fused plug to BS 1363-1 with half-insulated pins, connecting to a BS 1363-2 socket. The specification prohibits, in terms:
- extension cables;
- multi-way adaptors;
- travel adaptors;
- RCD adaptors;
- plug converters.
The plug goes into the wall socket, or it does not go in at all. A socket on a spur behind a wardrobe is not suitable; nor is one shared with a tumble dryer.
Anti-islanding, and why the plug has extra contacts
A grid-connected inverter must stop exporting when the grid goes away, so that it cannot energise wiring an engineer believes is dead. The specification requires anti-islanding protection tested to the relevant standard, and additionally requires protection against hazardous voltages at the plug pins — either a mechanical shutter or locking arrangement, or an electromechanical disconnection that works independently of the main anti-islanding function.
This is why a compliant kit's plug is not an ordinary plug with a label on it, and why substituting a different plug or an adaptor defeats the safety design.
The pre-purchase checklist
- Is the kit on the ENA Type Test Register in the plug-in solar category?
- What type are the RCDs on the circuit you intend to use — Type A, or Type AC?
- Does the consumer unit have RCBO protection, or is it an older fuse board?
- Is the socket the kit will use on its own final circuit, with nothing else drawing heavily from it?
- Do the manufacturer's instructions name your mounting surface, and does the specification permit it?
- Is there written permission if you rent or lease?
If any answer is unsure, the step is an electrician's visit, not a purchase.
Sources and limits
- Plug-in Solar Device Interim Product Specification, version 2 — clauses 4.1, 5.7, 6.2.3 and the installation instruction requirements.
- Electrical Safety First, plug-in solar panels.
- Energy Networks Association, connecting generation to the electricity networks — the G98 notification route.
This is a consumer guide, not an electrical design. Whether a particular installation is safe is a judgement for a competent electrician who has seen it.