Laying Conduit/ Building Duct Banks Flashcards
PVC ducts can bend up to ? per section without requiring special curved pieces.
5 degree
Ducts are installed at least ? below final grade level.
24”
High-voltage conductors are buried at least ? below grade.
36”
Ducts for each utility are usually stacked with ? on the bottom, and ? of vertical separation between each row of conduit.
Electrical Cables
6”
Electric and Communication utilities usually share a manhole.
True
Duct banks need to be surrounded by at least ? of concrete to bleed off heat
3”
What is the maximum recommended ducts in a typical configuration is
9 conduits ina 3x3 configuration
To reduce friction, the conduit is much larger than the conductor, and all bends should have a large radius.
true
Use synthetic rope to pull conductors to prevent burning the walls of the conduit around bends.
True
Most existing underground transmission lines use welded steel pipe for conduit. These pipes can be filled with high-pressure oil to help transfer heat away from the conductor.
true
On straight pulls, it is rare for the distance between manholes to be greater than ? .
500’
PVC conduit is available in lengths ranging from five feet up to ? .
30’
For economic reasons, the ? power cable system can be used. It is the type used mostly in underground residential distribution.
direct bury
To avoid collecting water, duct runs should have ? .
slight slopes
When drawing cables through conduits, pull speeds of less than ? are recommended for single conductor pulls.
60fpm
