Installing Cable in Underground Vault or Manhole

Question 1

Cables should be sealed with paraffin or shrink wrap caps when? Why?

Answer 1

When left overnight or for more than eight hours.
Prevent moisture from entering the cable

Question 2

Cables should be ? in a manner which will prevent the cable from ? at the point where it enters the manhole or vault.

Answer 2

Supported
Kinking

Question 3

If a manhole is to have the cable looped between the entrance and the exit, the cable should circle the manhole at least ?

Answer 3

360 degrees

Question 4

Where manholes are not to be looped, the cable should be routed on the walls ?

Answer 4

with the longest distance between points of entry and exit.

Question 5

Cables should be arranged to avoid ?

Answer 5

interference with duct or worker entrances into the manhole.

Question 6

Cables should be routed in a manner that will allow adequate room for bending and terminating the cables.

Answer 6

true

Question 7

Cables must be supported in a way that will not result in cable weight being placed on the termination point.

Answer 7

true

Question 8

Cable bending radius is to be at least ? the cable diameter.

Answer 8

12 times

Question 9

Cables should not be directly fastened to support channels with wire or plastic ties.

Answer 9

true

Question 10

Cables should be secured to racks with ? or mounted on a heavy-duty nonmetallic multi-mount cable support.

Answer 10

porcelain insulators and clamps

Question 11

At least two racks should be installed in parallel on each manhole wall. The cable should not be supported by just one rack support in the manhole.

Answer 11

True

Question 12

At least one spare hook should be installed at each cable rack position for future cable installations.

Answer 12

True

Question 13

Cable racks should be secured to the walls of the manhole with 3∕8 inch-16 drop-in anchors with a rated pullout working capacity of at least 2,100 pounds.

Answer 13

true

Question 14

Bolts installed in vaults and manholes should be made of 303 stainless steel, rated for use in underground devices.

Answer 14

True

Question 15

The ? is the only part of a power cable that can take a fairly high pulling tension.

Answer 15

core conductor(s)

Question 16

When pulling in cable using a wire-mesh grip with a swivel eye, the pulling tension is usually less than ? .

Answer 16

1,000lbs

Question 17

One way a duct can be checked for proper diameter and obstructions is to ? through the conduit.

Answer 17

pull a flexible steel mandrel

Question 18

If a cable is required to make a smooth low-friction 90° turn in a vault, a ? or lip-roller block would be used.

Answer 18

quadrant

Question 19

A weak link installed at the pulling eye acts as a mechanical fuse and breaks apart before a cable is overstretched during pulling operations.

Answer 19

true

Question 20

Depending on the jurisdiction, underground utility vaults (manholes) more than ? deep are considered to be an enclosed space.

Answer 20

4’

Question 21

To avoid an explosion caused by a spark, before removing the cover, remote probes are used to test the atmosphere of an enclosed space for oxygen deficiency, ? and vapors.

Answer 21

flammable gases

Question 22

When a blower is used to provide fresh air in an enclosed space such as a manhole, a blower with a capacity of ? cfm or greater is used.

Answer 22

1,000

Question 23

Historically, about 60% of fatalities involving confined spaces occur when ? .

Answer 23

attendants perform a rescue

Question 24

An impending fault is indicated when a cable in a vault has abnormalities such as oil or compound leaking, broken cable sheaths, hot localized surface temperatures, or swollen splices. When energized cables show symptoms of these types, the cable should be ? before anyone works in the vault.

Answer 24

de-energized

Question 25

When ventilating a vault (manhole) with a blower, the space should be ventilated for at least ? before entering.

Answer 25

5 min