A Mounting plate (200, 210) and a mounting frame (300, 310) are provided. These allow providing an easy attachment of an electrical device (100) to a wall or ceiling without using tools such as screws or the like, and which allows easy interchange, which also can be applied to mounting boxes (400) which follow different standards. The mounting plate (200, 210) includes an aperture (201) for receiving at least part of the device, and attachment means (202, 203, 212) for attaching the mounting plate (200, 210) to a mounting box (300, 310), and at least one clamping hook (600, 610, 620) with an elongated arm (602, 612, 622) for fixing the position of a mounting of the electrical device (100). The clamping hook (600, 610, 620) can engage with a cavity or slot (302, 313) of the frame (300, 310) by inserting the hook (600, 610, 620) in the slot (302, 313) of the frame (300, 310) and rotating or shifting the frame (300, 310) so the arm of the hook (600, 610, 620) slides over the frame (300, 310). The mounting frame (300, 310) includes at least one receiving portion (302, 313) adapted to fit at least one clamping hook (600, 610, 620) of the mounting plate (200, 210). An installation system including both the mounting frame (300, 310) and the mounting plate (200, 210) and method of manufacture the mounting plate are provided.