General Requirements for Cabinets and Racks

A cabinet or rack must belong to one of the following types:

• Standard 19-in. four-post EIA cabinet or rack, with mounting posts that conform to English universal hole spacing per section 1 of ANSI/EIA-310-D-1992. See Requirements Specific to Perforated Cabinets and Requirements Specific to Solid-Walled Cabinets.
• Standard two-post telco rack, with mounting posts that conform to English universal hole spacing per section 1 of ANSI/EIA-310-D-1992.

The cabinet or rack must also meet the following requirements:

• The minimum vertical rack space per chassis should be 1 RU, equal to 1.75 in. (4.4 cm).
• The width between the inside edges of the mounting posts must be at least 17.75 in. (45.1 cm). This is the distance between the two front posts of the four-post EIA racks.
• The minimum rack-load ratings per RU are listed in the following table:

  Rack Type	IBM SAN32C-6
  EIA (4 post)	7.5 lb (3.4 kg)
  Telco (2 post)	15 lb (6.8 kg)

• For four-post EIA cabinets (perforated or solid-walled):
  • The minimum spacing for bend radius for fiber-optic cables should have the front mounting posts of the cabinet offset from the front door by a minimum of 3 in. (7.6 cm).
  • The distance between the outside face of the front mounting post and the outside face of the back mounting post should be 26 to 32 in. (66 to 81 cm) to allow for rear-bracket installation.
  • The distance between the rear of the chassis and the perforated rear door of the cabinet (required for airflow in the cabinet, if used) should be 3.0 in. (7.6 cm).
  • No clearance is required between the chassis and the sides of the rack or cabinet (no side airflow).