WorksheetsThe Electrical System and Electric Service
Total questions: 15
Worksheet time: 8mins
Which component is part of a building’s electrical system and is used to measure electricity consumption?
Service panel
Meter
Receptacle
Switch
Electricity is supplied to a typical building via a service drop that includes three wires. What is the role of the third wire?
It carries 240V continuously
It synchronizes the two hot wires
It is the neutral or ground at zero volts
It converts AC to DC
A clothes dryer requires 240V. Using the information about opposite AC voltages, which connection provides 240V?
One hot wire to neutral (120V − 0V)
Two neutrals (0V − 0V)
Between the two hot wires (120V − (−120V))
Hot wire to ground (120V − 0V)
Which statement best defines electric power as presented?
The total amount of energy stored in a device
The rate at which energy is used
The maximum voltage a circuit can handle
The cost charged by the utility company
What is the standard unit used to measure electric power?
Volts
Amperes
Watts
Ohms
In a building’s main electrical panel, what is the purpose of the main breaker compared with the smaller circuit breakers?
The main breaker measures energy use; smaller breakers distribute power.
The main breaker distributes power; smaller breakers measure current.
The main breaker allows all power to be switched off; smaller breakers allow individual circuits to be switched off.
The main breaker increases voltage; smaller breakers decrease voltage.
In standard building wiring, which color typically identifies the hot wire inside a sheathed cable?
Black
White
Green
Blue
On a standard receptacle, which feature correctly matches the prong pattern?
Hot slot is longer than the neutral slot
Neutral slot is longer than the hot slot
Grounding socket is rectangular
Both slots are the same length by code
Which statement best describes the function of a receptacle?
It converts AC to DC for devices.
It is an outlet that connects devices to power and continues the circuit through hot, neutral, and ground wires in the cord.
It only provides a ground connection for safety.
It measures current flow in a circuit.
Where are Ground-Fault Circuit Interrupters (GFCIs) required by code due to potential exposure to water?
Bedroom and hallway
Garage and attic
Kitchen and bathroom
Living room and dining room
What does a GFCI do when a short circuit occurs?
Closes the circuit to reroute current
Opens the circuit to stop current
Reduces voltage to a safe level
Switches power to the neutral line
Which statement best describes a single-pole electrical switch based on the diagram of one switch controlling one light?
It allows switching from two locations.
It allows switching from one location to open or close a single circuit.
It controls two independent circuits from one location.
It automatically varies light brightness.
A double-pole/single-throw (DPST) switch is most appropriate when you need to:
Control one circuit from two locations.
Control two separate circuits simultaneously from one location.
Dim a single light from one location.
Convert AC to DC in a circuit.
According to the three-way electrical switch illustration, what capability does a three-way switch provide?
Switching a circuit from one location only.
Switching two circuits from one location.
Switching a single circuit from two locations.
Automatically turning lights on at sunset.
You are reading an electrical plan that uses a rectangular fixture symbol with a circle in the middle and triangular shapes on the sides. According to the legend, what does this symbol represent?
8" fluorescent light
Ceiling light – 100W
2 x 4 (4 lamp) parabolic troffer light
Electric panel
