Insulators

Question 1

Conductors on overhead lines are electrically insulated from the ground by either resting on insulators or being ? .

Answer 1

suspended from insulators

Question 2

Three materials used for overhead line insulators are porcelain, polymer, and ? .

Answer 2

glass

Question 3

If three phases and a neutral are mounted on a crossarm, the neutral can be identified as it is the one mounted on a ? insulator.

Answer 3

glass

Question 4

A combination of dirt and moisture will cause insulators to flash over; ? is/are also a likely cause.

Answer 4

lightning

Question 5

The glaze on a porcelain insulator helps the insulator’s surface shed dirt and bead water.

Answer 5

true

Question 6

Pin-type insulators can be two or more pieces cemented together.

Answer 6

true

Question 7

A one-piece insulator can withstand a higher voltage than a two-piece insulator.

Answer 7

False

Question 8

Hand wire ties or ? ties are used to fasten a conductor on most top tie insulators.

Answer 8

preformed

Question 9

Each disk of a porcelain or glass suspension insulator is rated at ? .

Answer 9

11 kV

Question 10

A porcelain suspension insulator uses a ball-and-socket design which puts the insulating material under ? to create strength.

Answer 10

compression

Question 11

One piece porcelain pin-type insulators are used on lines where the voltages are less than ? .

Answer 11

23 kV

Question 12

A polymer suspension insulator cannot withstand the tension of deadend conductors.

Answer 12

False

Question 13

Pin insulators are no longer used on transmission lines.

Answer 13

true

Question 14

If a suspension insulator string is made up of 50 kip insulators, the insulator string is able to withstand ? of tension.

Answer 14

50,000 lbs

Question 15

Post insulators are positioned on a pole to support conductors in a vertical or horizontal ? position.

Answer 15

cantilevered

Question 16

Post insulators are most likely to be found when a line is built on a ? or along a highway.

Answer 16

narrow right-of-way

Question 17

When hoisting a long string of insulators, care should be taken not to ? because it can damage the ball, socket, and cotter keys.

Answer 17

excessively bend the string

Question 18

Polymer insulators are light weight but do not maintain high dielectric or mechanical strength.

Answer 18

False

Question 19

It is acceptable to climb down a polymer insulator to the conductor level on a transmission line.

Answer 19

False

Question 20

A 240-kilovolt suspension insulator string is likely to have ? porcelain insulators.

Answer 20

14

Question 21

A 69-kilovolt suspension insulator string is likely to have ? porcelain insulators.

Answer 21

4 or 5

Question 22

The diameter of suspension porcelain insulator disks varies from 3 3/8 to ? .

Answer 22

11 1/2”