Quiz 2

Question 1

Key design elements for static dissipators based on point discharge theory (3)

Answer 1

1. Radius of dissipator electrode
2. Number of dissipator electrodes
3. Dissipator construction material

Question 2

Improving earth resistance include (3)

Answer 2

1. Treat soil
2. Use of multiple rods
3. Lengthen the earth electrode in the earth

Question 3

This method of measuring earth resistance is best applied when a simple ground system with existing return path through a multiple grounds is present.

Answer 3

Clamp-on

Question 4

The typical duration of a lightning flash is approximately…

Answer 4

0.5 seconds

Question 5

The National eElectrical Code recommend additional electrode if a resistance to ground greater than…

Answer 5

25 ohms

Question 6

Basic test method for earth resistance measurements include (3)

Answer 6

1. Clamp-on test method
2. Dead earth method
3. Fall of Potential method

Question 7

The most common source of lightning cloud form is…

Answer 7

Cumulonimbus

Question 8

In the British standard, S1 means…

Answer 8

Strike directly to the structure

Question 9

A lightning flash is a constant source of…

Answer 9

current

Question 10

Methods of designing the air termination network includes (3)

Answer 10

1. The rolling sphere
2. The protective angle design
3. The mesh design

Question 11

Types of LPS earthing system include (3)

Answer 11

1. Type A
2. Type B
3. Foundation earth electrodes

Question 12

Factors affecting earth resistivity (3)

Answer 12

1. Temperature
2. Type of soil
3. Moisture content

Question 13

The average peak current for the first impulse of lightning is…

Answer 13

18kA

Question 14

British design of lightning protection system is based on… (3)

Answer 14

1. Rolling Sphere method
2. Protective angle/Cone method
3. Use of natural conductors

Question 15

Most common form of lightning that account for 90% or more of the cloud-to-ground flashes worldwide is…

Answer 15

Category 1

Question 16

Refers to location where at risk of full lightning strike and the full lightning electromagnetic field.

Answer 16

LPZ 0a

Question 17

The minimum recommended thickness of stainless steel sheet considered as part of LPS is…

Answer 17

0.50 mm

Question 18

It is a positive leader ground-to-cloud discharge.

Answer 18

Category 2

Question 19

The cone of protection is determined by the following (2)

Answer 19

1. Height of structure
2. Storm Cloud

Question 20

The lightning protection system is required to… (3)

Answer 20

1. Conduct the lightning strike safely to ground
2. Disperse the strike safely in the earth
3. Intercept the lightning strike