90.2 Cable race ways. Shelters should be equipped with separate
ferrous-type closed cable race ways for RED signal and control, BLACK signal
and control, RED power, and BLACK power cables. Race ways should be
separated by at least 3 feet (0-9 m).
90.3 Doors. Doors should be made of metal material. They should be bonded
to the skin of the shelter with flexible conductive straps and should
incorporate RFI gasketing. Doors should be constructed so they can be locked
from the inside. One-way, wide-angle, through-the-door viewers should be
installed to provide a means of positive visual identification prior to
opening the door.
90.4 Shelter grounding points. Multiple grounding points should be provided
on external surfaces of the shelter to provide multiple ground current paths
to earth. At least two ground terminals should be installed at diagonal
corners of the shelter. All cable entrance plates should be equipped with
ground terminals. The inner and outer skins of the shelter should be bonded
together with multiple terminals provided on the inner skin.
90.5 Entrance panels. Power and signal entrance panels should be separated
by the maximum allowable distance. When a shelter is designed to have RED
and BLACK lines penetrating the shelter skin, separate RED and BLACK panels
should be provided with at least 3 feet (0.9 m) of separation. The ideal
configuration would be to have RED and BLACK panels on opposite sides of the