Abstract: A multiphase medium voltage vacuum contactor is disclosed which can include a mounting frame on which there are positioned: for each phase, a current interrupter having a vacuum bulb which contains a fixed contact and a corresponding movable contact; and an actuator for moving the movable contacts between a closed position where they are coupled each to a corresponding fixed contact and an open position where they are each electrically separated from the corresponding fixed contact, and an electronic unit driving the actuator. An exemplary voltage transformer for feeding the electronic unit can be mounted on the frame. One or more sacrificial fault-protection devices and/or current sensors can be operatively associated to the voltage transformer and embedded into an electrically insulating coating encasing the transformer.