Dell PowerEdge 1750 - Manual (Page 24)

1-18 Ra c k I n s t a l l a t i o n G u i d e
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4 Installing the cable-management arm
5 Routing cables
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 1-13).
F i g u r e 1 - 1 3 . Tw o - P o s t , O p e n - F r a m e R e l a y R a c k U n i v e r s a l - H o l e S p a c i n g
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 1-14).
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])
5X860eb0.fm Page 18 Monday, October 21, 2002 11:49 AM