Consider the location of monorails, equipment removal spaces, and floor
hatches in the layout design so that raceways do not interfere with
Use of drip shields where piping lines cross over cable trays.
Cable trays should be located away from heat sources such as steam
lines and hot process piping wherever possible. When locating cable
trays away from heat sources is not possible, analyses may be required
to determine if high-temperature cable and/or heat shielding may be
required. Cable trays should also be located away from potential fire
hazards such as lube oil and fuel oil storage tanks.
Raceways which require multiple cable trays may be installed in a vertical
or horizontal (side by side) arrangement as required by the facility
configuration. When arranged horizontally, a minimum distance of 30
inches shall be provided along one side of each tray run to allow for
installation and maintenance. When two trays are run side by side, the
access space may be common. When arranged vertically (trays above
each other) cable trays shall have a minimum vertical spacing of 16
inches for trays which have a 3-inch loading depth and 17 inches for trays
which have a 4-inch loading depth to allow for maintenance and
installation and to permit the use of cable pulling equipment when
For modifications of existing facilities, existing raceways may be used, where
feasible, to install new cables. The following guidelines should be considered to
prevent cable damage:
Additional new cables should not exceed the allowable raceway fill
guidelines of IEEE-1185.
When power cables are added, evaluate the current capacity of all cables
(existing and new) within the raceway.