A backup circuit keeps the essentials running during a power cut: the fridge, the heating controls, the router. If you want more, such as the cooker, the washing machine and the lights in every room, you need a changeover switch. With it, your storage system powers the whole house.
What a changeover switch does
The changeover switch sits in the meter cabinet and decides where your house gets its power from: the public grid or your storage system. In everyday use it is set to grid. If the grid fails, you flip it by hand. It then disconnects all three phases and the neutral conductor from the grid and connects your house to the backup output of the inverter. This way no power flows from your storage system into lines that someone may be working on.
What happens during a power cut
- The grid fails. If you have a backup circuit, it keeps running automatically after no more than 10 ms.
- You go to the meter cabinet and switch the changeover switch to storage.
- The whole house has power again, with up to 10, 15 or 20 kW for all circuits together, depending on the model.
- When the grid comes back, you switch it back to grid.
How much power you have
In whole-home backup mode, all circuits share the power of the backup output: 10 kW with the HM10-H, 15 kW with the HM15 and 20 kW with the HM20. The inverter handles short peaks, for example when a motor starts, with 120 % for 30 seconds. Lights, fridge, TV and washing machine usually need only a few kilowatts together. Large loads such as an instantaneous water heater, a sauna or a wallbox are best not switched on at the same time during this period.
How long the power lasts
That depends on the size of your storage system and on your consumption. An example: if your household uses around 10 kWh a day, a full 30 kWh storage system lasts just under three days on paper. When the sun shines, your PV system keeps charging the storage during the outage, so the power lasts even longer. All three series grow in steps of 10 kWh up to 90 kWh. You can work out which size suits you in the storage configurator.
Installation and versions
The changeover switch is installed in your meter cabinet by a qualified electrician, at Acada by our trade partners, compactly and in line with VDE standards. We install it in two versions, for 40 A and for 63 A. The electrician checks on site which one suits your house connection. The changeover switch is available for the three-phase systems HM10-H, HM15 and HM20. The easiest way is to plan it in right away when you buy your storage system.
You can find both versions in the shop, the price does not include installation: 40 A · 63 A
Backup circuit and changeover switch together
You are best covered with both: the backup circuit kicks in immediately without you doing anything, and the changeover switch brings in the rest of the house during a longer outage. The difference between the two is explained in the article Backup circuit or whole-home backup? The difference, simply explained
Want to plan in the changeover switch right away? Write to us using the contact form.
More about the systems: HM10-H · HM15 · HM20
Terms such as whole-home backup, backup circuit and switching time are explained in the Acada Energy Guide (in German).
Answers to further questions about power outages and backup power can be found in our FAQ (in German).