Midwest Electricâs Terminal Boxes Are For Use In Converting From Overhead to Underground Services and For Multi-Circuit Wiring. The Nema 3R Enclosure Provides Protection For All Terminations Inside and Provides A Convenient, Timesaving Means Of Wire Splices and Connections. Midwest Offers A Full Line Of Terminal Boxes For 240-Volt, Single-Phase and 600-Volt, Three-Phase Ratings. Typical Applications, Both Indoors and Outdoors, Include Inter-Building Wiring On Farms, Convenient Splicing Means For Industr