The CN4SB403 is a 400/400 A CU/AL, 3-wire splitter box in the CN4SB series of Type 4/3R mild steel splitter boxes. Its 24 x 17 in body and 6 in depth give electricians room to split a 400 A, 3-wire feed with factory installed splitter blocks. The series is designed for distribution of up to 600 A (max) service, 600 V max, with 75° C conductor ampacity permitted.

The series table lists 24.00 x 17.00 x 6.00 in (610 x 432 x 152 mm) H x W x D. The part page gives a nominal size of 24 x 17 x 7 in, and the drawing shows 6.85 in overall depth. Drawing details include a 23.97 x 16.97 in door, a 22.52 x 15.39 in door opening, a 22.17 x 15.17 in inner panel, and Ø0.50 in wall mounting holes on 22.50 x 15.50 in centres.

The body is formed 16 gauge steel with smooth, continuously welded seams ground smooth. A formed lip and seamless poured-in place gasket exclude flowing liquids and contaminants. Splitter blocks come factory installed (reference CSBL400). The door is secured with quarter turn slot latches that need a tool, hangs on 304 stainless steel hinges with stainless steel pins, is removable and interchangeable, and has stiffeners where required. Enclosure and cover are finished in recoatable smooth ANSI 61 gray powder coating; the included inner panel is white and mounts on collar studs.

The CN4SB403 is CSA Type 3R, 12, 4 and complies with IEC 60529, IP66. A hardware kit with panel mounting nuts and sealing washers is included, grounding kit CGK400 is optional, and the box ships boxed at 38 lbs (17.24 kg).