Alcatel-Lucent 7750 SR-a4, Installation Manual, Page: 59 / 232

Site Preparation
7750 SR-a4 and SR-a8 Installation Guide 59
Torque Specifications for Rack Mounting
Racks and rack-mounting screws are not supplied by Alcatel-Lucent. EIA-310 defines four
screw sizes: 10-32, 12-24, M5, and M6. Each screw size has a different typical torque value,
which can vary depending on the material used in the manufacture of the rack and screws.
Table 27 lists some typical torque values.
Chassis Location Requirements
Observe the following requirements when installing the system horizontally in the 19-in.
(482.6 mm) rack.
• Maintain clearance around the chassis as shown in the shaded areas in Figure 15 and
as described in Table 28 .
• Ensure that the inlet and exhaust of the chassis is free of obstructions from cabling,
mounting hardware, or other electronic equipment in the area.
Warning: Always follow the rack manufacturer’s instructions regarding screws and torque.
Table 27: Typical Torque Values for Rack Mounting the Chassis
Screw Size Typical Torque
10-32
18-20 lbf-in (2.03 to 2.25 N
.
m)
12-24
24-28 lbf-in (2.71 to 3.16 N
.
m)
M5
20-22 lbf-in (2.25 to 2.48 N
.
m)
M6
34-38 lbf-in (3.84 to 4.29 N
.
m)