The present invention provides an electrical device (1), the device comprising: a housing (6) electrical circuitry in the housing, wherein the walls of the housing define a cavity (11) having a first end (12) that is open to the exterior of the device and a second end (13) that is inside the housing, the housing having a first fixing arrangement (14) at the first end (12) of the cavity and a second fixing arrangement (15) at the second end (13) of the cavity, wherein the first and second fixing arrangements are each capable of fixing a power connection insert (20,30,40) in position and, a power connection insert (20,30,40) fixed by either the first or second fixing arrangement (14,15), wherein the power connection insert and that fixing arrangement are constructed and arranged to mechanically interlock with each other, wherein the power connection insert provides a power cable (43) or power connector, said power cable or power connector being electrically connected to said electrical circuitry such that external electrical power can be supplied to the device via the power cable or power connector.
