Basic Electrical Materials and Methods cont'd

DOE-HDBK-1132-99

Consider the location of monorails, equipment removal spaces, and floor

hatches in the layout design so that raceways do not interfere with

equipment removal.

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

required.

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.

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