How plug-in solar works: panels, inverter and socket

A plug-in solar kit is a small solar power system that you connect to your home through a normal socket. One or two solar panels produce direct current, a microinverter converts it into alternating current at mains voltage and frequency, and a cable with a plug feeds it into the wiring of your flat or house. Whatever your fridge, router or washing machine is drawing at that moment is covered first by the solar power. Only the surplus leaves your home through the meter.

That is the whole principle. There is no battery in the basic kit, no wiring work and, within the rules of your country, no installer. The rest of this guide explains each part, what happens to the electricity and where the limits are. For the rules country by country, see the country rules hub.

The four parts of a kit

Part	What it does	What to look for
Solar panels	Turn sunlight into direct current (DC)	Rated output in Wp, size and weight, frame type
Microinverter	Converts DC into grid-synchronised AC	AC output (often 800 VA), number of inputs, certificates
Cable and plug	Connects the inverter to the home wiring	Plug type permitted in your country, cable length
Mounting	Holds the panels at an angle to the sun	Approval for your balcony, wall or ground, wind load

Panels

Most kits use standard rooftop-size panels. Their rating in watt-peak (Wp) describes output under laboratory test conditions, not on your balcony. In real use, a panel rarely reaches its peak rating, because angle, temperature and shading all reduce output. That is one reason why many kits pair more panel capacity with an inverter that is capped lower.

Microinverter

The microinverter is the heart of the system. It tracks the best operating point of each panel, converts the power and synchronises it with the grid. It also contains the protection that switches it off when the grid voltage disappears. In Germany this behaviour is defined in the grid connection rules for small generators (VDE-AR-N 4105); in Great Britain, small generators are covered by the network rules in Engineering Recommendation G98.

Plug and socket

The plug type depends on the country. In Great Britain, the 2026 rules allow plug-in solar through a standard 13 A socket. In Germany the familiar Schuko plug is now covered by a product standard, provided the device meets its safety requirements; a special energy socket remains an option. Either way, the kit should go into a wall socket, not into an extension lead or a multi-way adapter.

Where the electricity goes

Electricity takes the path of least resistance to wherever it is being used. When your kit produces 400 W and your home is using 250 W, the 250 W are covered by the panels and 150 W flow out through the meter into the grid. When your home uses 1,000 W, the kit covers 400 W and the remaining 600 W come from the grid as usual.

This has two consequences:

• Self-consumption is what saves money. Every kilowatt-hour you use directly replaces one you would otherwise buy. What you export is usually unpaid for plug-in kits, although schemes differ by country.
• Timing matters. Panels produce most around midday, when many households use little. Base loads such as a fridge, a router or standby devices run all day and soak up part of the output. Running a dishwasher or washing machine at midday raises the share further.

You can estimate your own figures with our yield and payback calculator. If much of your output would be exported, a battery can shift it into the evening; see plug-in solar with a battery.

Safety built in

Two safety questions come up most often.

Are the plug pins live when I unplug it? No. The inverter only produces power while it detects a stable grid. When you pull the plug, it loses that reference and switches off. Certified inverters are tested for this.

Can the wiring be overloaded? A socket circuit is protected by a fuse or circuit breaker that only sees the current coming from the consumer unit. Power fed in at a socket adds to that, so the cable could in theory carry more than the breaker allows. That is the main reason for the output cap, explained in detail in our guide to the 800 W limit. If your wiring is old or you are unsure about its condition, ask an electrician to check it before you plug anything in.

What the kit cannot do

• No backup power. Because the inverter switches off when the grid fails, a standard kit does nothing in a power cut.
• No unlimited size. You cannot add more inverters or kits behind each other without breaking the rules in most countries; the cap applies per household or connection.
• No fixed installation work. Anything beyond plugging in a certified kit, such as a new socket or a dedicated circuit, belongs in the hands of a qualified electrician.

Before you buy

1. Check the rules for your country, including registration, on the rules pages.
2. Look at your socket and the circuit behind it.
3. Work out where the panels can go and which way they will face; see mounting options.
4. Estimate yield and self-consumption before you compare prices.

For the official technical background on PV output at your location, the European Commission’s free PVGIS tool is a good starting point.