L02M09 Grounding and Bonding
 
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L02M09 Grounding and Bonding

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
A ground fault is described as an unintentional _____.
a.
connection between two or more portions of the equipment grounding conductor
b.
open connection between an electrical circuit or equipment and the earth
c.
conducting connection between any of the conductors of an electrical system
d.
electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors
 

 2. 
Where a main bonding jumper is required by the NEC®, the jumper cannot be less than what percentage of the area of the largest phase conductor?
a.
12.50%
b.
14%
c.
17.50%
d.
20%
 

 3. 
A ground test utilizing an auxiliary current electrode and an auxiliary potential electrode is known as the _____.
a.
one-point test
b.
three-point test
c.
six-point test
d.
ten-point test
 

 4. 
If Single-Gang, Nail-on, nonmetallic boxes are used with NM cable, which of the following is true?
a.
No connection to the box is required.
b.
A grounding clip connects the box to the cable.
c.
Electrical tape connects the box to the cable.
d.
A standard electrician’s staple connects the box to the cable.
 

 5. 
The fall-of-potential method is used to measure _____.
a.
induced currents
b.
step voltage
c.
earth resistance
d.
touch voltage
 

 6. 
Rod, pipe, and plate electrodes must have a resistance to ground of at least _____.
a.
25 ohms or less
b.
35 ohms or less
c.
45 ohms or less
d.
75 ohms or less
 

 7. 
In a separately derived system, the equipment bonding jumper connects the _____.
a.
system housing to the neutral bus bar
b.
system housing to the feeder panel
c.
neutral on the supply side to the equipment housing
d.
neutral bus bar to the grounding electrode conductor
 

 8. 
Which type of system is required to be grounded?
a.
Systems less than 50V supplied by grounded transformers
b.
Circuits for cranes that operate over combustible fibers in Class III locations
c.
AC systems over 1kV that supply mobile or portable equipment
d.
Circuits for electrolytic cells
 

 9. 
The size of the equipment grounding conductor (EGC) is determined by the _____.
a.
size of the overcurrent device protecting the system
b.
length of the conduit
c.
size of the neutral
d.
size of the largest conductor
 

 10. 
Which of the following is true when installing grounding at more than one building?
a.
Only the equipment grounding conductor is extended to the second building.
b.
The second building never requires its own grounding electrode.
c.
The equipment grounding conductor from the main building is terminated on a bus isolated from the rest of the cabinet.
d.
The grounded circuit conductor and the equipment grounding conductor must both be extended to the second building.
 

 11. 
A transformer-supplied system operating at less than 50V must be grounded if the supply voltage to the transformer exceeds _____.
a.
24V
b.
50V
c.
120V
d.
150V
 

 12. 
To be effective, a grounding system must limit the voltage on the electrical system and protect it from _____.
a.
contact with the earth
b.
voltage surges
c.
vandalism
d.
undervoltage conditions
 

 13. 
A short circuit is a conducting connection between _____.
a.
ungrounded conductors
b.
ungrounded connectors and non-current carrying conductors
c.
grounded connectors and non-current carrying conductors
d.
any of the conductors of an electrical system
 

 14. 
Which of the following is an NEC® requirement for grounding and bonding?
a.
The path to ground from circuits, equipment, and metal enclosures shall be continuous.
b.
The path to ground from circuits, equipment, and metal enclosures shall have sufficiently high impedance to facilitate the operation of protective devices.
c.
The path to ground from circuits, equipment, and metal enclosures shall rely on the earth as an effective ground fault current path.
d.
The path to ground from circuits, equipment, and metal enclosures shall be capable of safely carrying twice the maximum current of the system.
 

 15. 
The minimum length allowed for driven ground rods under normal conditions is _____.
a.
4'
b.
8'
c.
10'
d.
16'
 

 16. 
The requirements for grounding of services are located in _____.
a.
NEC Article 250, Part III
b.
NEC Sections 250.24(A), (B), (C), and (D)
c.
NEC Section 250.52(A)(2)
d.
NEC Section 250.64
 

 17. 
System grounding relates to the _____.
a.
EGCs
b.
systems over 250 volts
c.
service-entrance equipment
d.
rod and pipe electrodes
 

 18. 
The maximum value of a short circuit current from line-to-neutral (grounded) _____.
a.
is 120V
b.
is 240V
c.
will vary depending on the distance from the source to the fault
d.
is the maximum capacity of the system
 

 19. 
The bonding jumper for multiple disconnecting means is located _____.
a.
on the supply side of the service disconnect
b.
between the equipment and the equipment grounding bus
c.
between the feeder panel and the equipment
d.
between the equipment and ground bar
 

 20. 
The minimum diameter of galvanized pipe allowed for a grounding electrode is _____.
a.
1/2"
b.
3/4"
c.
1"
d.
1-1/4"
 

 21. 
Which of the following is true of the neutral in a grounded system?
a.
It precludes utilization of power at line-to-neutral voltage.
b.
It prevents the current carrying conductor from carrying an unbalanced load.
c.
It supersedes the operation of overcurrent devices.
d.
It provides a low-impedance return path for the flow of fault current to the source.
 

 22. 
The continuity between service equipment and enclosures is maintained by _____.
a.
solder
b.
metal raceways
c.
bonding
d.
grounding electrodes
 

 23. 
A separately derived system is a premises wiring system that is _____.
a.
limited to DC power
b.
grounded directly to the grounding electrode conductor
c.
completely contained in one building
d.
powered from a source other than a service
 

 24. 
When a ground rod is installed, the top of the rod must be positioned _____.
a.
below permanent moisture level if practicable
b.
4" above grade
c.
6" above grade
d.
10" above grade
 

 25. 
Which of the following must have at least 2 square feet of surface area exposed to the surrounding earth?
a.
Equipment grounding conductor
b.
Rod electrode
c.
Pipe electrode
d.
Plate electrode
 



 
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