What an Electrician Does When Installing a Home Battery
- Installation follows the wiring regulations (BS 7671) and the IET Code of Practice for Electrical Energy Storage Systems.
- A battery cannot be switched off like an ordinary circuit, so isolation and clear labelling matter.
- Keeping some circuits live in a power cut needs a switching arrangement, not just a bigger battery.
- The grid connection must be notified to the network operator under G98 or G99.
- This is general information, not a method statement: the installer's own competence and the maker's manual come first.
A home battery is not a plug-and-forget appliance. A good installer surveys the property, mounts and wires the unit, fits isolation and labels, and then tells the network operator. Knowing the steps helps you spot a rushed job.
The survey comes first
A sensible job starts before any tool comes out. The installer looks at where the unit will go, how the cable will run from the consumer unit, what the existing solar and inverter setup is, and whether the supply can take the extra equipment. Location is a real decision: the IET's guidance says no UK standard prohibits an indoor installation and that the choice rests with the installer or manufacturer, while noting that outdoor siting is preferable for fire safety if the battery can be kept in its temperature range (IET battery storage Q&A). Our guide to where to put a home battery in the house goes through the options.
The same IET page says loft spaces may be unsuitable because of access, weight and temperature extremes. If a quote simply says "loft" without explaining how the unit will be reached and supported, ask.
Mounting, wiring and isolation
The unit is fixed following the manufacturer's clearances for ventilation and separation from combustible material. A UK government review of domestic battery safety says the installation must follow the Wiring Regulations, that those regulations have no chapter specific to batteries, and that the installation section for solar (712) and the IET Code of Practice are useful references (GOV.UK domestic battery storage review, PDF). That review dates from 2020, so treat it as background rather than the current rulebook. We saw a third edition of the IET Code of Practice listed by the IET, which is the document your installer should be working from.
Isolation is the part owners rarely think about. The IET page points out that batteries cannot be switched off, so domestic packs are usually enclosed with a way to disconnect their output. The government review recommends a double-pole battery isolator close to the battery to cut the DC supply to the inverter, and says DC protective devices must be rated for current flowing both ways when the battery and inverter are separate.
- AC wiring from the battery or inverter to a protected circuit in the consumer unit.
- DC wiring between battery modules and the inverter, where the system is DC-coupled.
- Isolators and protective devices sized for the equipment.
- Data or communication cable between battery, inverter and meter, so the software can see what the house is doing.
Good to know
We have not described cable sizes or torque values. The IET page we read gives no domestic cable guidance, and these details come from the manufacturer's instructions and the installer's design.
Backup circuits and island mode
If you want some circuits to keep working in a power cut, the system has to be able to run separately from the grid, often called island mode. The IET page says a switching arrangement is usually needed to form island mode, and that powering a whole property from a simple system, like a UPS, is generally not possible. In practice that means a chosen set of essential circuits, such as lights, the fridge and the router, is moved onto a backup supply. See whole home battery backup for what that looks like.
The IET page adds that where island-mode capability exists, BS 7671, IET guidance and G98/G99 call for adequate information and labelling, and that a system diagram and maintenance procedures should be provided for many domestic systems.
Commissioning and telling the network
Once wired, the installer tests the system, sets the inverter's grid settings, checks that it behaves correctly when the grid is lost, and explains the app. The IET page says that a system that switches between connected and island modes usually needs G98 or, more likely, G99 notification, while a DC-side-only battery with no island-mode components is unlikely to need a new notification. Our explainer on G98 and G99 covers the difference.
Before you pay the final invoice, ask for the system diagram, the commissioning record, the notification confirmation and the manual. Those papers matter later for warranty claims, insurance and selling the house.
Common questions
Can I install a home battery myself?
Connecting a battery to the home's wiring and the grid is notifiable and safety critical. Our DIY or professional installation guide explains why most owners use a competent installer.
Does a battery need its own circuit?
Usually it is wired to a protected circuit from the consumer unit, but the exact arrangement depends on the design and the manufacturer's instructions. Your installer should show it on the system diagram.
Who decides where the battery goes?
The installer and the manufacturer, based on the maker's instructions and the property. The IET page we read says no UK standard prohibits indoor installation, so ask the installer to explain the choice.
Related guides
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