Cabinet; Site Influences - Alcatel-Lucent 7705 SAR-A Installation Manual

Cabinet

There are three major classifications of cabinets.

Site Influences

Is backup power generation located in the same area as the communications equipment? Are
batteries located in the same area as the equipment?
Backup generators that are located in the same enclosed area as the communications
equipment may cause a great deal of site pollution, such as nitrous oxides and hydrogen
sulphides, which can be detrimental to the long-term reliability and performance of
equipment. A best practice is to house motor generator sets in a separate enclosure from the
communications equipment. Batteries will outgas during charge and discharge cycles. These
gases are very corrosive and may also be explosive in sufficient concentration. Batteries
should always be housed in a properly vented enclosure or compartment, separate from the
communications equipment.
Is the equipment located above the water grade? Is there adequate water drainage and leak
controls?
Many areas are prone to flooding during rainy season or spring thaws, and it is important for
the site to be located above typically anticipated flood levels, or to have sump pumps to keep
the installation site dry. Drainage with backflow preventers should be installed if the site has
provision for water sources, such as cooling towers.
What protection is there to prevent entry of insects, pests, and vermin?
7705 SAR-A Chassis Installation Guide
• Direct Air Cooled (DAC) cabinets bring air into the cabinet to cool the equipment.
DAC cabinets may or may not be filtered. Unfiltered air intake and exhaust is not
recommended since issues will occur if unfiltered air is allowed into the cabinet. The
ideal filter is a hydrophobic filter (GORE) since it filters particles smaller than 1
micron. Hydrophobic filters will prevent passage of water droplets but still allow
water vapor to pass. Some chemical pollutants may require carbon or other types of
filters particularly suited to the type of pollution.
• Heat Exchange (HEX) cabinets use a sealed cabinet and a heat exchanger to
withdraw heat from the cabinet interior without bringing outside air into the cabinet.
This results in no contamination influx and low humidity within the cabinet.
• Air Conditioned (AC) cabinets use a mechanical or Thermal Electric Cooling (TEC)
refrigeration unit to handle higher levels of heat in high-power installations. AC
implementation is similar to HEX since the cabinet should be sealed. Proper AC
implementation should never allow unfiltered air into the cabinet interior.
Site Preparation
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