ch 1 Flashcards
The practical safeguarding of persons and property from hazards arising from the use of electricity best describes which of the following?
The purpose of the NEC
If a conductive part is connected to ground or to a conductive body that extends a ground connection it is ? .
grounded
Which of the following best defines the word ground?
earth
When electrical systems or equipment are grounded, the ground (Earth) is part of the electrical circuit.
true
The Earth as a conductive body can serve as an effective ground-fault current path to facilitate the operation of fuses or circuit breakers protecting the system.
false
conductive body that extends the ground connection?
Equipment bonding jumpers
Equipment grounding conductor
Grounding electrode conductor
The frame of an automobile or airplane is not grounded.
true
The conductive object directly connected to Earth through which grounding is established, is provided by which of the following?
Grounding electrode
Which of the following is accomplished through electrical bonding?
Conductivity
Connecting together
Continuity
Bonding minimizes potential differences between conductive parts that are bonded together. It also safeguards against shock hazards, and in many cases ensures an effective path for ground fault current.
true
The processes of grounding and bonding work simultaneously to reduce potential differences between conductive parts and the Earth, thereby reducing shock hazards.
true
A(n) ? occurs when electrical current in a circuit returns through the equipment grounding conductor (EGC), through conductive material other than the electrical system ground (metal, water pipes, and so forth), through a person or through a combination of these ground return paths.
ground fault
Which of the following conditions is a factor in a person receiving an electric shock?
The current must exit through a second contact point.
There must be a contact point on the body for entry of the circuit current.
There must be a voltage to force the current across the human body.
Current will take only the path of least resistance when attempting to return to the source.
false
Which of the following is a function of grounding electrical systems?
Limit line surges, or unintentional contact with lines of higher voltage
Limit potentials (voltages) imposed by lightning
Stabilize voltages during normal operation
Grounding includes two basic concepts: grounding of equipment and grounding of systems.
true
When an electrical system is grounded, one conductor of the system is intentionally connected to ground and is referred to by the NEC as the ? conductor.
grounded
If the Code provides a requirement to ground equipment, it generally implies that there will be either a direct connection to the Earth or a connection to ground through which of the following?
Equipment grounding conductor
Grounding electrode
Grounding electrode conductor
An unintentional, electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non–current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or Earth best defines which of the following?
Ground fault
Which of the following are characteristics of an effective ground-fault current path?
Intentionally constructed
Low-impedance electrically conductive path
Designed and intended to carry current during ground-fault conditions
A(n) ? is an electrically conductive path from the point of a ground fault on a wiring system through normally non–current-carrying conductors, equipment, or the Earth to the electrical supply source.
ground-fault current path
In an ungrounded electrical system there is normally no connection to Earth from any conductor supplied by the system, other than through distributed leakage capacitance.
true
In a grounded system, normally non–current-carrying electrically conductive materials that are likely to become energized, such as building metal framing and metal water piping, shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.
true
The total opposition to current in an AC circuit is known as circuit ? .
impedance
