Troubleshooting guide

Section 2, Engineering Guidelines - Power Dissipation Considerations
61186003L1-1D 2-11
MX2820 Heat Dissipation and GR-63-CORE
The following guidelines are intended to aid the designer and planner for installations of
shelves and meeting NEBS heat release objectives. Since the system supports M13 and STS-
1 modules, much forethought should be given to the installation and possible future
expansion. Depending on the technology employed, various scenarios and shelf densities can
be achieved. Refer to Figure 2-1and Figure 2-2 for examples of frame installations.
NOTE
An MX2820 installation that uses STS-1 modules should be
actively cooled.
Telcordia GR-63-CORE specifies the physical protection requirements and objectives for
telecommunications equipment. Often referred to as “NEBS” (Network Equipment-Building
System), these guidelines have become the de facto standard for U.S. telecommunications
equipment and include both requirements and objectives for heat dissipation.
The NEBS requirement is that the heat release of telecommunications equipment be
documented. For the system, this is done in the “Power Dissipation for an MX2820 Shelf”
section.
Shelf Level
NEBS further provides specific objectives for heat dissipation within a shelf in paragraph
O4-12 of GR-63-CORE. For an equipment shelf such as the , the relevant values are as follows
in Table 2-12 (from GR-63-CORE Table 4-6).
Frame Level
NEBS provides specific objectives for heat dissipation in a frame in paragraph O4-12 for a
frame such as intended for the system. The relevant values are as follows in Table 2-13 (from
GR-63-CORE Table 4-6).
Table 2-12. Heat Dissipation for Shelf
Heat Release Method Requirements
Natural convection
740 W/m
2
per meter (20.9 W/ft
2
/ft) of vertical frame space the equip-
ment uses
Forced-air fans
995 W/m
2
per meter (27.9 W/ft
2
/ft) of vertical frame space the equip-
ment uses
Table 2-13. Heat Dissipation for Individual Frame
Heat Release Method Requirements
Natural convection
1450 W/m
2
(134.7 W/ft
2
)
Forced-air fans
1950 W/m
2
(181.2 W/ft
2
)