Racks + enclosures · 3 min read

How to Size a Network Rack or Wall Cabinet

Rack units, 2-post vs. 4-post, depth and growth space — a quick checklist before you order.

Count your rack units

Rack height is measured in rack units (U). One U is 1.75 inches. List every patch panel, switch, cable manager, shelf, UPS and power strip you plan to mount and add up the U.

Choose the style

  • 2-post open racks: easy access for patch panels and lighter equipment.
  • 4-post racks: support deeper, heavier equipment such as servers and UPS units.
  • Wall-mount racks and cabinets: good for small telecom rooms and closets; check depth and door clearance.
  • Enclosed cabinets: add security and dust protection — plan for ventilation or fans.

Before you order

  • Leave room to grow — many installers plan for roughly 25–30% open space.
  • Plan horizontal cable management between patch panels and switches.
  • Check equipment depth and weight against the rack’s rating.
  • Confirm power: outlets, circuit capacity and whether a UPS is needed.

General guidance only — always follow project specifications, manufacturer instructions and local code.

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