ESSENTIAL ELECTRICAL SKILLS FOR HVACR - CHAPTER 1:
ELECTRICAL SAFETY COMPREHENSIVE PRACTICE QUESTIONS
1. What is a live electrical circuit?
A) A circuit that has been disconnected from its power source
B) A circuit that is being supplied with electrical energy
C) A circuit that is connected to a grounding rod
D) A circuit that contains only insulated wires
Correct Answer: B - A live electrical circuit is one that is being supplied with
electrical energy, meaning it has voltage present and can cause shock or injury .
2. Electrical shock occurs when a person:
A) Touches an insulated wire
B) Touches an electric motor that is properly grounded
C) Becomes part of an electric circuit
D) Touches a conductor that has no power applied
Correct Answer: C - Electrical shock occurs when a person becomes part of an
electric circuit, allowing current to flow through their body .
3. Which of the following voltages will an HVACR technician commonly come in
contact with?
A) 24 volts only
B) 120 volts only
C) 240 volts only
D) All of the above
Correct Answer: D - HVACR technicians commonly work with 24V (control
circuits), 120V (standard outlets), and 240V (large equipment) .
,4. What is the standard by which electrical installations are measured in the
United States?
A) United Electrical Code
B) National Electrical Code (NEC)
C) Basic Electrical Code
D) International Electrical Standard
Correct Answer: B - The National Electrical Code (NEC) is the standard by which
electrical installations are measured in the United States .
5. A current flow of 0.1 ampere or less:
A) Is completely safe for human contact
B) Could be fatal to a person
C) Is only dangerous if the voltage is above 240V
D) Will only cause minor discomfort
Correct Answer: B - A current flow of 0.1 ampere (100 milliamperes) or less can
be fatal to a human being .
6. Which type of ladder should a technician use on the job?
A) Aluminum only
B) Fiberglass only
C) Wood only
D) Fiberglass or wood
Correct Answer: D - Fiberglass and wood ladders are acceptable for electrical
work because they do not conduct electricity, unlike aluminum ladders .
7. Which prong on a three-prong plug is the ground?
A) The left flat prong
,B) The right flat prong
C) The center semicircular prong
D) The top flat prong
Correct Answer: C - On a three-prong plug, the center semicircular prong is the
grounding prong .
8. A grounding adapter does no good if it is:
A) Made of metal
B) Connected to an electrical ground
C) Not connected to an electrical ground
D) Used with a three-prong cord
Correct Answer: C - A grounding adapter (cheater plug) provides no protection if it
is not properly connected to an electrical ground .
9. What is the correct fuse size for an electrical circuit?
A) Twice as large as needed for circuit protection
B) Three times as large as needed for circuit protection
C) Sized appropriately for circuit protection, not oversized
D) Any size that physically fits the fuse holder
Correct Answer: C - The correct fuse size is one that is properly sized for the
circuit, not oversized, as oversized fuses create a fire hazard .
10. What is the primary purpose of a GFCI (Ground Fault Circuit Interrupter)?
A) To protect equipment from voltage spikes
B) To protect people from electrical shock
C) To measure current flow in a circuit
D) To provide grounding for ungrounded outlets
, Correct Answer: B - A GFCI is designed to protect people from electrical shock by
detecting ground faults and quickly interrupting the circuit .
11. When working around live electrical circuits, the most important thing to
remember is to:
A) Work quickly to minimize exposure
B) Respect the electricity and use safe procedures
C) Wear cotton gloves for protection
D) Keep one hand in your pocket at all times
Correct Answer: B - The single most important element when dealing with
electrical circuits is to respect them and always use safe procedures when power
is on .
12. What should you do when you see a coworker receiving an electrical shock?
A) Immediately pull them away from the source
B) Do not touch them while they are in contact with an electrical source
C) Pour water on them to break the circuit
D) Call 911 and leave them alone
Correct Answer: B - You should not touch a person receiving a shock while they
are in contact with an electrical source, as you could also become part of the
circuit. Proceed with caution and request medical attention .
13. True or False: A heating and air-conditioning service technician can usually
troubleshoot systems without the voltage being supplied to the equipment.
A) True
B) False
Correct Answer: B - A technician cannot usually troubleshoot heating and air-
conditioning systems without voltage being supplied to the equipment, although
some checks can be performed with power off .
ELECTRICAL SAFETY COMPREHENSIVE PRACTICE QUESTIONS
1. What is a live electrical circuit?
A) A circuit that has been disconnected from its power source
B) A circuit that is being supplied with electrical energy
C) A circuit that is connected to a grounding rod
D) A circuit that contains only insulated wires
Correct Answer: B - A live electrical circuit is one that is being supplied with
electrical energy, meaning it has voltage present and can cause shock or injury .
2. Electrical shock occurs when a person:
A) Touches an insulated wire
B) Touches an electric motor that is properly grounded
C) Becomes part of an electric circuit
D) Touches a conductor that has no power applied
Correct Answer: C - Electrical shock occurs when a person becomes part of an
electric circuit, allowing current to flow through their body .
3. Which of the following voltages will an HVACR technician commonly come in
contact with?
A) 24 volts only
B) 120 volts only
C) 240 volts only
D) All of the above
Correct Answer: D - HVACR technicians commonly work with 24V (control
circuits), 120V (standard outlets), and 240V (large equipment) .
,4. What is the standard by which electrical installations are measured in the
United States?
A) United Electrical Code
B) National Electrical Code (NEC)
C) Basic Electrical Code
D) International Electrical Standard
Correct Answer: B - The National Electrical Code (NEC) is the standard by which
electrical installations are measured in the United States .
5. A current flow of 0.1 ampere or less:
A) Is completely safe for human contact
B) Could be fatal to a person
C) Is only dangerous if the voltage is above 240V
D) Will only cause minor discomfort
Correct Answer: B - A current flow of 0.1 ampere (100 milliamperes) or less can
be fatal to a human being .
6. Which type of ladder should a technician use on the job?
A) Aluminum only
B) Fiberglass only
C) Wood only
D) Fiberglass or wood
Correct Answer: D - Fiberglass and wood ladders are acceptable for electrical
work because they do not conduct electricity, unlike aluminum ladders .
7. Which prong on a three-prong plug is the ground?
A) The left flat prong
,B) The right flat prong
C) The center semicircular prong
D) The top flat prong
Correct Answer: C - On a three-prong plug, the center semicircular prong is the
grounding prong .
8. A grounding adapter does no good if it is:
A) Made of metal
B) Connected to an electrical ground
C) Not connected to an electrical ground
D) Used with a three-prong cord
Correct Answer: C - A grounding adapter (cheater plug) provides no protection if it
is not properly connected to an electrical ground .
9. What is the correct fuse size for an electrical circuit?
A) Twice as large as needed for circuit protection
B) Three times as large as needed for circuit protection
C) Sized appropriately for circuit protection, not oversized
D) Any size that physically fits the fuse holder
Correct Answer: C - The correct fuse size is one that is properly sized for the
circuit, not oversized, as oversized fuses create a fire hazard .
10. What is the primary purpose of a GFCI (Ground Fault Circuit Interrupter)?
A) To protect equipment from voltage spikes
B) To protect people from electrical shock
C) To measure current flow in a circuit
D) To provide grounding for ungrounded outlets
, Correct Answer: B - A GFCI is designed to protect people from electrical shock by
detecting ground faults and quickly interrupting the circuit .
11. When working around live electrical circuits, the most important thing to
remember is to:
A) Work quickly to minimize exposure
B) Respect the electricity and use safe procedures
C) Wear cotton gloves for protection
D) Keep one hand in your pocket at all times
Correct Answer: B - The single most important element when dealing with
electrical circuits is to respect them and always use safe procedures when power
is on .
12. What should you do when you see a coworker receiving an electrical shock?
A) Immediately pull them away from the source
B) Do not touch them while they are in contact with an electrical source
C) Pour water on them to break the circuit
D) Call 911 and leave them alone
Correct Answer: B - You should not touch a person receiving a shock while they
are in contact with an electrical source, as you could also become part of the
circuit. Proceed with caution and request medical attention .
13. True or False: A heating and air-conditioning service technician can usually
troubleshoot systems without the voltage being supplied to the equipment.
A) True
B) False
Correct Answer: B - A technician cannot usually troubleshoot heating and air-
conditioning systems without voltage being supplied to the equipment, although
some checks can be performed with power off .
