NCCER Electricity Level 3 Section 9
Questions and Answers | Latest Version
| 2024/2025 | Correct & Verified
What happens to the current when the voltage in a circuit is increased?
✔✔Increasing the voltage causes the current to increase as well, according to Ohm’s Law,
assuming the resistance stays constant.
Why do power plants use alternating current (AC) for long-distance power transmission?
✔✔AC can be easily transformed into higher or lower voltages, which makes it more efficient
for transmitting power over long distances with minimal energy loss.
What is the purpose of a busbar in an electrical system?
✔✔A busbar is a conductive material that distributes electricity from one source to multiple
circuits, acting as a central hub for power distribution.
What does a ground fault interrupt in an electrical system?
✔✔A ground fault interrupts the flow of electricity if there is an unintended path to the ground,
protecting people from electrical shock.
1
, What is a variable frequency drive (VFD) used for in electrical systems?
✔✔A VFD is used to control the speed and torque of an electric motor by adjusting the
frequency of the power supply.
How does a light dimmer switch work?
✔✔A dimmer switch works by adjusting the power supplied to the light, often by chopping the
AC waveform to reduce the amount of energy delivered.
What could happen if you connect a 240V device to a 120V outlet?
✔✔The device may not work properly or could be damaged, as it is receiving less voltage than it
requires for operation.
Why are insulated wires used in electrical circuits?
✔✔Insulated wires prevent accidental contact with conductive materials or other wires, reducing
the risk of electrical shock or short circuits.
What does a wattmeter measure?
✔✔A wattmeter measures the amount of power, in watts, that is being used in a circuit.
2
Questions and Answers | Latest Version
| 2024/2025 | Correct & Verified
What happens to the current when the voltage in a circuit is increased?
✔✔Increasing the voltage causes the current to increase as well, according to Ohm’s Law,
assuming the resistance stays constant.
Why do power plants use alternating current (AC) for long-distance power transmission?
✔✔AC can be easily transformed into higher or lower voltages, which makes it more efficient
for transmitting power over long distances with minimal energy loss.
What is the purpose of a busbar in an electrical system?
✔✔A busbar is a conductive material that distributes electricity from one source to multiple
circuits, acting as a central hub for power distribution.
What does a ground fault interrupt in an electrical system?
✔✔A ground fault interrupts the flow of electricity if there is an unintended path to the ground,
protecting people from electrical shock.
1
, What is a variable frequency drive (VFD) used for in electrical systems?
✔✔A VFD is used to control the speed and torque of an electric motor by adjusting the
frequency of the power supply.
How does a light dimmer switch work?
✔✔A dimmer switch works by adjusting the power supplied to the light, often by chopping the
AC waveform to reduce the amount of energy delivered.
What could happen if you connect a 240V device to a 120V outlet?
✔✔The device may not work properly or could be damaged, as it is receiving less voltage than it
requires for operation.
Why are insulated wires used in electrical circuits?
✔✔Insulated wires prevent accidental contact with conductive materials or other wires, reducing
the risk of electrical shock or short circuits.
What does a wattmeter measure?
✔✔A wattmeter measures the amount of power, in watts, that is being used in a circuit.
2
