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 MIL-HDBK-1012/3
distribution panel sizing is based on amperage service and
circuit breaker quantity. The RCDD should ensure electrical
service panels are sized to provide for expansion of the
equipment room service by specifying a minimum oversizing of 50
percent (e.g., if the baseline electrical requirements are 100
amperes and 24 circuit breakers, specify 150 amperes and 36
circuit breakers). If it is within budget and building service
availability, 100 percent oversizing is preferable. Each
equipment cabinet or rack should be assigned its own circuit
breaker rated to meet the current load of the equipment within
the cabinet. Each cabinet should be labeled front and back with
the panel number and the circuit breaker assignment. Power
strips, with sufficient outlets to accommodate the equipment
assigned plus two for portable test equipment and tools, should
be installed in the cabinet. In addition to the outlets
available within the equipment cabinets, dual receptacle wall
outlets should be placed around the room. NFPA 70, Section
210-52 and EIA/TIA 569, par. 9.5.5.6.1 establish a minimum of
1.83 m (6 ft.) between receptacles. Wall outlets should be
placed 155 mm (6 in.) above the floor. At least one wall outlet
should be connected to the backup power service panel if
available. It is recommended that backup power facilities
(generators, uninterruptible power supply (UPS), etc.,) be
provisioned with an automatic switching and filtering capability
to preclude loss of service or transient damage to the electronic
equipment.
1.9.5
Equipment Room Structural Considerations. The
multitude of installation options for electronic equipment and
cable routing in an equipment room require the RCDD to ensure the
room will structurally accommodate most installation practices.
Structural considerations consist of floor type, wall mounting,
and interior cable management support.
1.9.5.1
Flooring. Two primary types of flooring are used in
equipment rooms: access floors and concrete floors which are
usually either covered with antistatic tile or painted. Details
regarding access flooring are described in par. 1.5.1.1.f) of
this handbook. Determining the selection of the floor type is
dependent upon several factors. The first element to be
considered is the volume and flexibility requirements of the
cabling to be routed within the room. If the claimant
anticipates extensive growth of systems over the life cycle of
the room, or the probability of routine access to the cable
pathways is high, then it is recommended that an access floor be
used. Information affecting load bearing computations for the
equipment, cabinets, and cable should be provided to the
structural engineer for inclusion in new building design. When
an equipment room is being planned for a renovated building, the
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