Worksheets146 S13 Grounding Material
Total questions: 20
Worksheet time: 2hrs 40mins
Name
Class
Date
1.
What is a key characteristic of a good grounding system?
a)
a) High electrical resistance
b)
b) High electrical conductivity
c)
c) Low mechanical strength
d)
d) High impedance
2.
What is one of the main purposes of a grounding system?
a)
a) To increase electrical resistance
b)
b) To limit transient overvoltage
c)
c) To disconnect the power supply
d)
d) To store electrical energy
3.
Which of the following is NOT a component of a grounding system?
a)
a) Grounding conductors
b)
b) Grounding connectors
c)
c) Grounding electrodes
d)
d) Grounding insulators
4.
What is the NEC requirement for grounding electrode resistance?
a)
a) Under 25 ohms
b)
b) Over 50 ohms
c)
c) Exactly 30 ohms
d)
d) Under 10 ohms
5.
Which material is NOT allowed for use as a grounding electrode?
a)
a) Copper
b)
b) Aluminum
c)
c) Steel
d)
d) Bronze
6.
What can accelerate corrosion in grounding systems?
a)
a) High voltage
b)
b) Presence of moisture
c)
c) Low temperature
d)
d) Lack of oxygen
7.
What combination of materials must be avoided in grounding systems to prevent electrolytic couples?
a)
a) Copper and steel
b)
b) Copper and bronze
c)
c) Aluminum and zinc
d)
d) Steel and iron
8.
What should be done to down conductors entering corrosive soil?
a)
a) They should be insulated
b)
b) They should be protected with a covering
c)
c) They should be made of aluminum
d)
d) They should be shortened
9.
Which material is most suitable for grounding systems due to its conductivity and corrosion resistance?
a)
a) Steel
b)
b) Copper
c)
c) Aluminum
d)
d) Zinc
10.
What type of ground electrodes are metal underground water pipes?
a)
a) Made electrodes
b)
b) Natural electrodes
c)
c) Synthetic electrodes
d)
d) Temporary electrodes
11.
What is a disadvantage of galvanized steel ground rods?
a)
a) High cost
b)
b) Short service life
c)
c) Excessive bending resistance
d)
d) High electrical resistance
12.
What type of ground rods are developed as a compromise between cost and performance?
a)
a) Solid copper rods
b)
b) Stainless steel rods
c)
c) Steel-cored ground rods with a copper or stainless steel sheath
d)
d) Aluminum rods
13.
What problem can occur with the sheath of steel-cored ground rods?
a)
a) Overheating
b)
b) Excessive bending
c)
c) Sheath slipping or tearing
d)
d) Electrical insulation
14.
What is a key feature of copper-bonded ground rods?
a)
a) Low tensile strength
b)
b) High electrical resistance
c)
c) Long-lasting molecular bond between copper layer and steel core
d)
d) High cost
15.
What should NOT be used as ground electrodes in grounding systems?
a)
a) Underground gas piping
b)
b) Copper rods
c)
c) Stainless steel rods
d)
d) Copper wire ring encircling the structure
16.
What factor influences the corrosion of grounding system components in soil?
a)
a) Soil type
b)
b) Electrical resistance
c)
c) Metal color
d)
d) Electromagnetic interference
17.
What is an advantage of stainless steel ground rods in certain soils?
a)
a) Low cost
b)
b) Compatibility with copper
c)
c) Resistance to corrosion in specific environments
d)
d) High electrical conductivity
18.
What is a typical use for natural ground electrodes in a building?
a)
a) Temporary grounding during construction
b)
b) Providing an earthing path using metal structures already in place
c)
c) Increasing electrical impedance
d)
d) Reducing grounding system cost
19.
What happens to a galvanized steel ground rod over time in soil?
a)
a) It gains conductivity
b)
b) It experiences zinc loss and excessive corrosion
c)
c) It becomes electrically insulated
d)
d) It decreases in length
20.
What is a major factor when selecting a ground rod besides resistance to corrosion?
a)
a) Initial cost only
b)
b) Serviceable life
c)
c) Color of the rod
d)
d) Length of the rod
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