Dell PowerVault 745N - Manual (Page 22)

22
Rack Installation Guide
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Marking the Rack
You must allow 1 U (44 mm or 1.75 inches) of vertical space for each system you install in the
two-post rack.
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 13).
Figure 13. Two-Post, Open-Frame Relay Rack Universal-Hole Spacing
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 vertical column of holes (see Figure 14).
Figure 14. Two-Post, Open-Frame Relay Rack Wide-Hole Spacing
12.7 mm (0.5 inch)
15.9 mm (0.625 inch)
15.9 mm (0.625 inch)
44 mm (1.75 inches [1 U])
44 mm (1.75 inches [1 U])
12.7 mm (0.5 inch)
31.7 mm (1.25 inches)