A solar and battery installation is, from the house's point of view, a new generating source connected into an installation that was designed to consume rather than produce. That changes what the consumer unit needs to do, how faults behave and what has to be labelled and isolated. This guide covers the electrical side rather than panel selection or financial return, because that is the part homeowners are least often shown.
How the system connects
Solar generation typically connects into the installation either through a dedicated way in the consumer unit or, on larger systems, at a separate point close to the incoming supply. Battery storage connects through an inverter, sometimes the same hybrid inverter that handles the panels.
The connection point matters. A dedicated protected way at the board is clean and easy to isolate. Connections made by spurring off an existing circuit are poor practice and should be questioned.
Consumer unit condition and capacity
A board that is already full, or that lacks modern protection, may need attention before a system can be connected properly. This is a common and legitimate finding, but it should be identified at survey, not raised on installation day.
Ask for the survey to include a look inside the existing board, a check of the main earthing and bonding, and confirmation of available ways. Main protective bonding to gas and water services is frequently found to be missing or undersized on older properties and must be corrected.
Isolation and labelling
Because the installation now has a source of energy that is not the incoming supply, isolation arrangements must be clear. There should be labelled means of isolating the generation and storage separately from the main switch, and warning labels indicating multiple sources of supply.
This is not paperwork for its own sake. It is what tells an electrician, or the fire service, that turning off the main switch does not necessarily make everything dead.
- Clearly labelled AC and DC isolation points
- Multiple supply warning labels at the consumer unit and meter
- A schedule showing which circuits the system can back up
- Documentation left with the property, not just emailed
Backup circuits and what they can run
Battery systems that provide power during an outage usually do so through a defined backup circuit or a limited set of circuits, not the whole house. Deciding which circuits those are is a real design decision: lighting, the fridge freezer, the router and a few sockets is a typical and sensible selection.
Electric showers, cookers and heat pumps are generally too large to back up meaningfully. Being told the system will run the house in a power cut is worth checking carefully against the inverter's actual output rating.
Notification and certification
The installation of a new circuit and connection of a generating source is notifiable work, and the network operator must also be notified of the generation being connected. You should receive an electrical installation certificate covering the new work, and the network notification should be confirmed in writing.
Keep this documentation. It is asked for at sale, and it matters if you later add a charge point or increase generation capacity.
Interaction with EV charging and heat pumps
If you are likely to add an EV charge point or heat pump later, mention it now. Total demand, spare ways at the board and available capacity all change, and it is far cheaper to size the board and containment once rather than twice.
Systems that can divert surplus generation to a charge point or hot water cylinder are worth considering at design stage, since retrofitting the control wiring afterwards is more disruptive.
Questions worth asking before you sign
A short list of questions separates a properly surveyed installation from a sales led one.
- Where exactly will the connection into my consumer unit be made?
- Does my board and bonding need any work first, and is that in the price?
- Which circuits will run in a power cut, and at what output?
- Who notifies building control and the network operator?
- What certificates and labels will I be left with?
After installation
Once commissioned, keep the labels, certificates and the network notification together with your other property documents. If you later have any electrical work done, tell the electrician there is generation and storage present before they start, because isolation is no longer a single main switch. Annual visual checks of the inverter, isolators and any external enclosures are sensible, and any error codes should be recorded rather than simply cleared.
Common questions
- Will I need a new consumer unit?
- Not always. It depends on available ways, existing protection and the condition of the board.
- Can a battery power my whole house in an outage?
- Rarely. Backup is normally limited to selected circuits within the inverter's output rating.
- Does bonding need upgrading?
- Often, on older properties. Main protective bonding to gas and water is checked as part of the survey.
- Is the work notifiable?
- Yes, and the network operator must also be notified of the generation being connected.
- Can I add an EV charger later?
- Yes, but tell the installer now so board capacity and containment are sized once.
We carry out the electrical side of solar and battery work, including board upgrades, bonding and certification.
Related guides
- Do I Actually Need a Consumer Unit Upgrade?An old board is not automatically a dangerous board, but some of them genuinely are.
- EV Charger Installation at Home: How It Actually WorksMost of the job happens before anyone drills a hole: the survey decides whether the installation is simple or awkward.
- Surge Protection Devices in a Domestic BoardAn SPD protects connected equipment from transient voltage spikes — not from every electrical mishap.