The 300 Series wall cabinets are welded with center-section depths of 12" and 15", respectively. Basic model includes three, 16-gauge CRS sections which include a 2" deep, solid-steel front door, a 12" or 15" deep center section with adjustable mounting rails, and a 4-1/2" deep rear door. Panel space openings range from 7 RU to 35 RU. Enclosures are equipped with provisions for custom cabinet mounting, wire man­agement, equipment mounting, and structural support. Cabinet is finished in #962 black epoxy.

All models include adjustable front rack rails tapped 10-32, and manufactured to standard E.I.A. 1/2" spacing. Models with RU openings of 16RU, 24RU and 35RU are equipped with center section mounting rail supports.

Internal open raceways provide cable pathways in the cabinet. Corner brace supports, which straddle the back and side panel of the rear section (hinge side), also feature round (1-1/4" diameter) wire access holes for harnessing excess wire. The back face of the rear section is equipped with 1/4" deep boss detents which give Contractors field flexibility to install a custom plywood, aluminum, or steel sub-plate for mounting accessories inside the cabinet. Boss detents are on 12" centers and vary depending upon model height (10RU, 12RU, and 16RU models have four detents, 24RU models have six detents and 35RU models have eight detents).

The cabinets have 20 conduit knockouts on the rear section, with the exception of the 307-12 which has 16. Conduit arrays are located at the top and bottom of the back panel (except 307-12 which has a centered array), as well as on the top and bottom back flanges. Panel arrays consist of four knockouts: two 1" (25mm) standard and two 1/2" (13mm) / 3/4" (19mm) concentric. Top and bottom flange arrays are comprised of six knockouts: three 1" (25mm) standard and three 1/2" (13mm) / 3/4" (19mm) concentric.