Dell PowerEdge SC1425 - Manual (Page 20)

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Rack Installation Guide
Figure 1-11. Two-Post, Open-Frame Relay Rack Wide-Hole Spacing
To mark the rack, perform the following steps:
1 Place a mark on the rack's front vertical rails where you want to locate the bottom of the
system you are installing in the two-post rack.
The bottom of each 1-U space is at the middle of the narrowest metal area between holes.
NOTE:
If your rack has wide-hole spacing, go to step 3.
2 Place a mark 44 mm (1.75 inches) above the original mark you made (or count up three holes
in a rack with universal-hole spacing) (see Figure 1-10).
Each 1 U (44 mm, or 1.75 inches) of vertical space on a rack with universal-hole spacing has
three holes with center-to-center spacing between holes (beginning at the top 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) (see Figure 1-10).
NOTE:
If your rack has universal-hole spacing, you have completed the procedure for marking
the rack.
3 Place a mark 44 mm (1.75 inches) above the original mark you made (or count up to the next
hole in the rack with wide-hole spacing (see Figure 1-11).
Each 1 U (44 mm, or 1.75 inches) of vertical space on a rack with wide-hole spacing has
two holes with center-to-center spacing between holes (beginning at the top of a 1-U space)
of 31.7 mm (1.25 inches) (see Figure 1-11).
Installing the Mounting Rails
You can install the mounting rails in a two-post, open-frame rack having either universal-hole
spacing (see Figure 1-10) or wide-hole spacing (see Figure 1-11). You can install the mounting rails
in either a flush-mount or center-mount configuration.
CAUTION:
Do not install another system using this rack kit. Use only the rack kit intended for your
system. Using the rack kit for another system may result in damage to the system and personal injury to
yourself and to others.
1 U (44 mm or 1.75 inches)
12.7 mm (0.5 inch)
31.7 mm (1.25 inches)