An apparatus (1) provided to connect at least one device (2) to a power distribution system (3), said apparatus (1) comprising a human machine interface, HMI, (4) having elements to interact with the apparatus (1), wherein the human machine interface elements (11,12) are adapted to display and/or to adjust setting values of operation parameters of the at least one connected device (2), wherein access to one or more human machine interface elements is restricted by at least one access restriction mechanism of said apparatus (1) to enhance the operation security of the at least one device (2) connected via said apparatus (1) to said power distribution system (3) and/or to enhance the operation security of the apparatus (1) and/or of the power distribution system (3).