Why a B10 circuit breaker is needed at 230V

Updated 9 October 2026Switchy

A B10 circuit breaker must be installed before the 230V channels of Switchy, experts call it a miniature circuit breaker (MCB). The 10 stands for 10A, the B for how quickly it trips. The reason: each 230V channel of Switchy is built for a maximum of 10A continuous current, and Switchy itself does not measure the current and does not switch off if there is too much current. The circuit breaker takes on this task.

Why 10A in particular?

The limit of 10A comes from the switching contacts and terminals in Switchy, they cannot handle more in continuous operation. If someone accidentally connects a device that is too large, for example a kettle with 12A, the circuit breaker must switch off before Switchy is damaged.

Why is B10 such a good fit?

  • It reliably switches off when more than 10A flows continuously.
  • It leaves enough headroom for the short current surge when switching on typical camper devices such as boilers, small pumps or household appliances under 10A.
  • It suits pitches that are often only fused at 6 to 10A.

Why B and not C?

A breaker with B trips quickly enough in the event of a short circuit, even if the fuse at the hook-up post is weak. A breaker with C would not manage this reliably.

What does not belong behind Switchy

Devices with a much higher current draw, for example air conditioning, a tumble dryer or an induction hob, get their own circuit breaker directly in the 230V distribution of your camper.

Also mandatory: for 230V operation, an RCD with 30mA (residual current device, protects against electric shock) must also be installed before Switchy. The entire 230V installation may only be carried out by a qualified electrician in accordance with DIN VDE 1000-10.

Related questions

What can I switch with Switchy?

Up to eight devices from one place: • 4 channels for 12V and 24V, each up to 30A, for example a pump, a fan or a lift bed • 4 channels for 230V, each up to 10A or 2300W, for example a boiler or sockets Appliances that draw much more, such as an air conditioner, a tumble dryer or an induction hob, do not belong behind Switchy. They get their own circuit breaker in the 230V distribution. More on this in [Switching loads with Switchy](/blogs/wissen/verbraucher-ueber-switchy-schalten).

Can I connect wall push buttons to Switchy?

No, Switchy has no push button inputs. You switch its channels on the SmartKnob or in the dashboard, also on a schedule or as part of a scene. If you also want to switch a device at the wall, connect it to Ampy or Lighty instead. There you can connect a push button to every output.

Does Switchy show what my devices consume?

No. Switchy switches, it does not measure. Ampy measures what each individual device draws, output by output. Battery and system data come from Volty. All three work together in the same dashboard.

Which fuses do I need for Switchy?

Switchy has no fuses of its own for the connected devices; they belong in the installation: • 12V and 24V: each channel gets its own fuse in the positive cable, no more than 30cm from the battery's positive terminal. • 230V: a 30mA residual current device and a B10 circuit breaker sit in front of Switchy. Only a qualified electrician may carry out the 230V installation. Why it has to be a B10 is explained in [Why a B10 circuit breaker is needed at 230V](/blogs/wissen/warum-lss-b10).

What happens if the shore power pillar is wired incorrectly?

Switchy checks the shore power continuously and shows you on the SmartKnob and in the dashboard whether everything is in order. • If the earth is missing, Switchy switches off all four 230V channels within milliseconds and the SmartKnob raises an alarm. Once the earth is back, you switch your devices back on yourself. That way nothing starts up unattended. • If live and neutral are swapped, it is almost always down to a Schuko plug or adapter. Pull the plug, turn it by 180 degrees and plug it back in. All the details in [What the AC input monitoring does](/blogs/wissen/was-die-ac-eingangsueberwachung-macht).

Can Switchy react automatically when I plug into shore power?

Yes. Switchy detects whether shore power is present, and you can use that as a trigger in the dashboard. For example, the boiler switches on as soon as you plug in at the campsite and off again when you unplug.

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