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 MIL-HDBK-1012/3
solid cement or block walls exist, which is common in buildings
being refurbished, a surface-mounted wireway must be attached to
the wall.
d) Cable sag should be minimized to reduce the stress
on the cables and to avoid interference with the removal of
ceiling tiles. A separation of 152 mm to 305 mm (6 in. to
12 in.) must be retained between the sag and the ceiling support
bar. Care must be taken to avoid sources of EMI, such as motors
(common in HVAC), power distribution cables, copy machines, and
Telecommunications cables and pathways
should cross fluorescent lights, conduits, and metallic cables at
right angles. Distances to be maintained from sources of EMI as
specified by EIA/TIA 569 are as follows:
(1)
1.3 m (4 ft.) from large motors and
(2) 27 cm (1 ft.) from cables and conduit used for
electrical power distribution; and
(3)
129 mm (5 in.) from fluorescent lighting.
1.5.1.3
Conduit Systems. With the exception of ceiling zone
distribution systems, conduit pathways are dedicated home run
paths from the station jack to the telecommunications closet. Up
to three jacks may be ganged together. These dedicated runs
result in reduced flexibility. Conduit may be constructed of
EMT, rigid metal conduit, or rigid polyvinyl chloride (PVC).
a)
Advantages of conduit distribution include:
(1) Placing conduit in the floor during
construction presents a low-cost unobtrusive path-to-wall outlet
in low user density areas;
(2) Conduit presents a clean solution to serving a
few floor outlets in an area where a ceiling distribution system
will be used to serve the majority of the users;
(3)
Eliminates the need for plenum cable; and
(4) Can be used to protect cables from corrosive
atmosphere or physical damage.
b) The following are the major disadvantages of
conduit systems:
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