An electrical unit (1) having a housing (5) having a first wall (7) and a circuit board (3) mounted inside the housing (5), wherein an inner side (7a) of the first wall (7) is provided with a mounting arrangement (17) for holding an electrical component (45).An outer side (7b) of the first wall (7) is provided with a disassembling marking (53, 55, 57) which corresponds to an outer boundary (65, 67, 69) of a mounting arrangement foundation designating a portion of the first wall which may be cut or removed upon disassembly of the electrical unit (39, 41, 43).