Ideal for those adding shorepower and an inverter at the same time. Incoming shorepower is protected by an RCD, a single breaker is provided that runs from shorepower only (ideal for running a battery charger, which should never be run from an inverter). An automatic changeover then selects between shore or inverter power (biased to shorepower). Power then runs through a second RCD and a breaker to run on board loads such as ring main ect.
Shorepower & Inverter Consumer Unit Datasheet