Electrical connection boxes for use in recreational vehicle and marine applications must be adapted for a variety of electrical services and electrical connection styles. In order to standardize electrical connection boxes for these uses, a plurality of positioning tabs may be mounted within the connection box to accommodate electrical connection receptacles of various sizes. Unused positioning tabs may be removed during assembly. Further standardization can be achieved through the use of gaskets adapted for use with power cords of different sizes but having common design features to mate with a common seating surface design.