Dell PowerEdge 850 Guide D'installation page 13

To mark the rack, perform the following steps:
1 Place a mark (or tape) on the rack's front vertical rails where you want to locate the bottom
of the system you are installing in the rack.
The bottom of each 1-U space is at the middle of the narrowest metal area between holes
(marked with a horizontal line on some rack cabinets—see Figure 1-4).
2 Place a mark 44 mm (1.75 inches) above the original mark you made (or count up three holes
in a rack that meets EIA-310 standards) and mark the rack's front vertical rails with a felt-
tipped pen or masking tape (if you counted holes, place a mark just above the top hole). This
mark or piece of tape indicates where the system's upper edge will be located on the vertical
rails (see Figure 1-4).
Figure 1-4. Marking the Vertical Rails
tape on vertical rail
Rack Installation Guide
11