grounding and bonding concept check
Which of the following cannot be used as a grounding electrode?
10' black iron gas pipe
If a circuit breaker ahead of a fault trips at 100 amperes of current, what is the maximum value of fault current that may flow through
100 amperes a fault?
Which one of the following systems does not have to be grounded?
24VAC control circuit
The maximum length of the conductor allowed when running a bonding conductor outside a raceway is _____.
6 feet
Where must the EGC originate in a separately derived system that originates in a transformer?
At the primary
Equipment grounding connects to which of the following?
Enclosures
System grounding connects the metal parts of the system like the boxes and motor frame to the electrical system's neutral conductor.
False
What is the EGC designed to carry?
Fault current
If a hot conductor contacts the metal enclosure of a panel, is this considered a ground fault or a short circuit?
Ground fault
What do we have if the neutral conductor contacts a metal receptacle box?
Ground fault
Which of the following items is not a component of the resistance of a grounding system?
Impedance of any transformers in the system
What NEC® article covers grounding and bonding?
NEC Article 250
Where would you find the requirements for sizing a grounding electrode conductor?
NEC Table 250.66
Which conductor carries unbalanced current?
Neutral
Can a standard ohmmeter be used to effectively measure the resistance of a grounding system?
No
Can a three-point resistance test be performed when only one electrode is installed?
No
Do you need to bond a plastic enclosure to the grounding system?
No
If multiple conduits enter an enclosure and the rules say that these conduits must be bonded, must you install a separate bonding jumper from each of them to the grounding terminals at the enclosure?
No
When running power from one building to another, must you always run both the EGC and the grounded conductor to the second building?
Only in certain conditions
Which of the following circuits must be grounded?
Separately derived systems
In a three-phase system, if Phase A conductor contacts Phase B conductor, what has taken place?
Short circuit
What factor determines the size of the EGC?
Size of the fuse in the circuit
Which of the following materials cannot be used as a grounding electrode conductor?
Stranded galvanized steel
Which one of the following methods should not be used to ground a metal residential receptacle box?
The bare ground wrapped around the screw that holds the receptacle
Why are all the noncurrent-carrying metal parts bonded together in a wiring system?
To provide a low=resistance path to ground
A metal underground tank or metal well casing can be used as a grounding electrode.
True
The grounded conductor and the grounding conductor are one and the same conductor and perform the same function.
false
The purpose of an effective grounding path is to conduct any _____ that might occur in the system.
fault current
To be effective, grounding systems must _____.
protect the system from lightning
Resistance to earth of a grounding electrode is commonly measured using the _____ method.
fall-of-potential