A carrier assembly for a harness for carrying a motor-driven power tool, the carrier assembly including a back plate and an interface plate including connections for shoulder straps. The back plate includes a coupling interface on a front face arranged to be removably connected to a corresponding coupling interface on a rear face of the interface plate. The coupling interface of the back plate is adapted to be connected to and disconnected from the coupling interface of the interface plate in an at least partially translational or linear movement which is substantially parallel to the back plate.