Lightning Protection

Question 1

The third part of the lightning protection system disperses the lightning strike safely into the earth. Which of the following materials are used for the third part of the lightning protection system?

Answer 1

Ground Rings
Ground Rod Electrodes
and Radials

Question 2

Class II materials are used on structures that exceed ? in height. They are generally larger or heavier than Class I materials.

Answer 2

75’

Question 3

Copper materials are made from the same grade of copper as ones used for commercial electrical work; these are generally designed to be ? conductive when annealed.

Answer 3

95%

Question 4

The minimum diameter of a Class I solid copper air terminal is ? .

Answer 4

3/8”

Question 5

The minimum requirements for a Class I aluminum main lightning conductor are ? strand size, 95 pounds/1,000 feet weight per length, and a cross-sectional area of 98,600 circular mils.

Answer 5

14 AWG

Question 6

When transitioning from aluminum to copper, fittings must be of the ? type.

Answer 6

bi-metallic

Question 7

Bimetallic connectors cannot be used within ? of the earth’s surface.

Answer 7

18”

Question 8

A conductor that encircles a structure that is in direct contact with the earth is called a ? .

Answer 8

Ground Ring Electrode

Question 9

Ground rods must be driven to a depth of not less than ? into the earth.

Answer 9

10’

Question 10

An electrical connection between an electrically conductive object and a component of a lightning protection system that is intended to reduce potential differences created by lightning currents is an example of bonding.

Answer 10

True

Question 11

Down conductors can be either Class I or Class II copper or aluminum lightning conductors (depending on the height of the structure) or structural steel that is at least ? thick.

Answer 11

3/16”

Question 12

All structures require at least two down conductors and at least one additional down conductor for every ? of roof perimeter over 250 feet.

Answer 12

100’

Question 13

Aluminum down conductors must transition to copper at a minimum of ? above where they come in contact with the earth, using a listed bimetallic connector.

Answer 13

18”

Question 14

It is permissible to install down conductors in gutters and downspouts; in fact, this is a good way to hide them.

Answer 14

False

Question 15

Aluminum conductors must not be installed in concrete or masonry; the alkali content of concrete would rapidly corrode aluminum.

Answer 15

True

Question 16

The space adjacent to a lightning protection system that is protected from a direct lightning strike is called the ? .

Answer 16

Zone of Protection

Question 17

Electrically continuous structural steel may be used as a strike termination device or main lightning protection conductor if it is at least ? thick.

Answer 17

3/16”

Question 18

Air terminals must be placed at or within ? of ridge ends on pitched roofs or at the edges and outside corners of flat or gently sloping roofs.

Answer 18

2’

Question 19

Air terminals that extend 24 inches or more above the object or area to be protected will be permitted to be placed at intervals not exceeding ? .

Answer 19

25’

Question 20

If the lightning conductor is run in metal conduit, it must be bonded to the conduit at ? .

Answer 20

• Any point where the conduit is not electrically continuous

- Both Ends

Question 21

Lightning conductors and all other lightning protection components concealed in steel reinforced concrete must be connected to the reinforcing steel at ? .

Answer 21

• The Lower Extremities

- The Upper Extremities

Question 22

Horizontal lightning conductor runs must be connected to the reinforcing steel at intervals not exceeding ? .

Answer 22

100’

Question 23

Grounded and ungrounded metal bodies exceeding ? in vertical length must be bonded to structural steel members as near as is practical to their extremities unless inherently bonded through construction at these locations.

Answer 23

60’

Question 24

The surge protection requirements outlined in NFPA 780 include both permanently installed and plug-in SPDs.

Answer 24

False

Question 25

Surge protective devices must be installed at all power service entrances.

Answer 25

True

Question 26

Surge protective devices must be installed at all points where an electrical or electronic system conductor leaves a structure to supply another structure if the conductors or cable are run over ?

Answer 26

100’

Question 27

Surge protective devices installed at the service entrance must have a minimum (Imax) rating of ? 8/20 per phase or a nominal discharge current (In) rating of ? 8/20 per phase.

Answer 27

40 kA / 20 kA