An electrical apparatus includes a secured functional unit, an unsecured functional unit and a supply device. The secured functional unit has a first interface device for secure communication and a control unit, and the unsecured functional unit has a second interface device for non-secure communication. The secured functional unit and the unsecured functional unit are designed for communicating with one another. The supply device further includes a supply unit. A first power path for supplying the secured functional unit is arranged between the supply unit and the secured functional unit, and a second power path for supplying the secured functional unit with electrical energy from the supply unit is arranged between the supply unit and the unsecured functional unit. A switch is arranged in the second power path. A second power path in the switch is looped in the first switching state and disconnected in the second switching state.