Dell PowerEdge 2650 2-Post Rack Installation - Page 9

Universal-Hole Spacing Racks Industry-standard two-post racks with universal-hole spacing have an alternating pattern of three holes per U with center-to-center hole spacing (beginning at the top hole of a 1-U space) of 15.9 mm, 15.9 mm, and 12.7 mm (0.625 inch, 0.625 inch, and 0.5 inch) for the front and back vertical column of holes (see Figure 1-2). Figure 1-2. Two-Post, Open-Frame Relay Rack Universal-Hole Spacing 44 mm (1.75 inches) (1 U) 15.9 mm (0.625 inch) 12.7 mm (0.5 inch) 15.9 mm (0.625 inch) 15.9 mm (0.625 inch) Wide-Hole Spacing Racks Some two-post racks with wide-hole spacing have an alternating pattern of two holes per U with center-to-center hole spacing (beginning at the top hole of a 1-U space) of 31.7 mm and 12.7 mm (1.25 inches and 0.5 inch) for the front and back vertical column of holes (see Figure 1-3). Figure 1-3. Two-Post, Open-Frame Relay Rack Wide-Hole Spacing 44 mm (1.75 inches) (1 U) 12.7 mm (0.5 inch) 31.7 mm (1.25 inches) 2-Post Rack Installation 1-5