The ornamental design for a combinedelectricalswitch with mounting plate, as shown and described.
1.-2. Combined electrical switch with mounting plate
2.1 : Perspective
2.2 : Front
2.3 : Left
2.4 : Back
2.5 : Top
2.6 : Bottom
2.7 : Perspective
In the reproductions, the broken lines are for the purpose of illustrating portions of the combined electrical switch with mounting plate that forms no part of the claimed design.