The CN4SB74 is the 4-wire, 70 A splitter box in the CN4SB series of Type 4/3R mild steel splitter boxes. Choose it over the 3-wire CN4SB73 when the service you are splitting carries a neutral as a fourth conductor. The series is designed for distribution of up to 600 A (max) service, 600 V max, using 3 or 4 wires, with 75° C conductor ampacity permitted; this size is rated 70/70 A CU/AL.

Enclosure dimensions from the series table are 12.00 in high, 10.00 in wide and 5.00 in deep (305 x 254 x 127 mm); the part page gives a nominal size of 12 x 10 x 6 in, and the drawing shows 5.85 in overall depth. The part drawing details an 11.97 x 9.97 in door, a door opening of 10.52 x 8.39 in, a 10.17 x 8.17 in inner panel and Ø0.50 in wall mounting holes at 10.50 x 8.50 in spacing.

The box is formed from 16 gauge steel with continuously welded seams ground smooth, a formed lip that excludes flowing liquids and contaminants, and a seamless poured-in place gasket. Splitter blocks come factory installed (reference CSBL125B). Door latches have a quarter turn slot requiring a tool, hinges are 304 stainless steel with stainless hinge pins, and doors are removable and interchangeable. Door stiffeners are provided where required. The enclosure and cover carry a recoatable smooth ANSI 61 gray powder coat, and the included inner panel is white.

Ratings are CSA Type 3R, 12 and 4 with IEC 60529, IP66 compliance. The CN4SB74 includes a hardware kit with panel mounting nuts and sealing washers, accepts optional grounding kit CGK125, and ships boxed at 12 lbs (5.44 kg).