Standard and Deluxe boxes are for 3-wire, 1 to 15 hp single-phase water systems that use standard/heavy-duty pressure switches, level switches, or other pilot devices. Deluxe boxes contain magnetic line contactors carefully matched to the motor rating, eliminating the need for external line contactors. The 15 hp XL Deluxe box has a larger enclosure that provides the space you need for heavy-duty wire and plenty of room for add-ons.