The raintight NEMA 3R power inlet box is designed for the use with the Pro/Tran transfer switches and Reliance Panel/Link manual transfer panels and generator-ready load centers. The power inlet box may be installed indoors, or outdoors in an open area where the generator is being used. Using one of the four combination 1/2-inch and 3/4-inch knockouts (one on each side, bottom and back) the power inlet box can be wired directly to the transfer switch or panel.