Non-standard/Universal hub opening. Hub no longer furnished, order U40 hub separately. Consult Manufacturer. Midwest ElectricÆs 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 industrial use, and commercial construction.