The CN4SB404 is the 4-wire, 400/400 A CU/AL splitter box in the CN4SB series of Type 4/3R mild steel splitter boxes with a hinged door and quarter turn latching. It is intended for electricians distributing a 400 A, 4-wire service through factory installed splitter blocks. The series is designed for distribution of up to 600 A (max) service at 600 V max, with 75° C conductor ampacity permitted.

The series ordering table lists the enclosure at 24.00 in high, 17.00 in wide and 6.00 in deep (610 x 432 x 152 mm), and the drawing shows an overall depth of 6.85 in. The part drawing shows a 23.97 x 16.97 in door, a door opening of 22.52 x 15.39 in, a 22.17 x 15.17 in inner panel, and Ø0.50 in wall mounting holes spaced 22.50 x 15.50 in.

Per the series specification the box is formed 16 gauge steel with smooth, continuously welded seams ground smooth, a formed lip to exclude flowing liquids and contaminants, and a seamless poured-in place gasket. Door latches have a quarter turn slot requiring a tool, hinges are 304 stainless steel with stainless steel pins, and the door is removable and interchangeable, with stiffeners where required. The splitter block reference for this size is CSBL400. Enclosure and cover are finished in recoatable smooth ANSI 61 gray powder coating, and the included inner panel is white, mounted on collar studs.

The series carries CSA Type 3R, 12, 4 ratings and complies with IEC 60529, IP66. A hardware kit with panel mounting nuts and sealing washers for the wall mounting holes is included, and grounding kit CGK400 is optional.