IA Master Residential Electrician Exam
Question 1. In a residential series-parallel circuit, which of the following statements is TRUE?
A) The total resistance is always the sum of all resistances.
B) The total current equals the sum of all branch currents.
C) The voltage across each branch in parallel is different.
D) The current through each series component is different.
Answer: B
Explanation: In a series-parallel circuit, each parallel branch carries its own current, and the total current
is the sum of the branch currents.
Question 2. What is the primary function of a transformer in a residential doorbell system?
A) Increase voltage for long-distance transmission
B) Convert AC to DC
C) Step down voltage to a safer level
D) Reduce current
Answer: C
Explanation: Residential doorbell transformers step down the standard line voltage (120V) to a much
safer voltage (often 16-24V) suitable for doorbell operation.
Question 3. If a residential circuit has a power factor of 0.7, what does this indicate?
A) The circuit is highly efficient
B) The current and voltage are perfectly in phase
C) There is significant reactive power present
D) The load is purely resistive
Answer: C
Explanation: A power factor less than 1 indicates the presence of reactive (non-working) power,
meaning current and voltage are not perfectly in phase.
Question 4. What is the primary reason for calculating available short-circuit current at a residential
panel?
A) To size the conductors
B) To select appropriate overcurrent protection devices
C) To determine lighting load
D) To ground the system
Answer: B
Explanation: Knowing the available short-circuit current helps in selecting circuit breakers or fuses rated
to safely interrupt fault currents.
Question 5. Which statement about protective device coordination is CORRECT for residential systems?
A) Only the main breaker needs to trip during a fault
B) All protective devices should operate simultaneously
C) Downstream breakers should trip before upstream devices
D) Fuses and breakers cannot be used together
Answer: C
Explanation: Proper coordination ensures that only the device closest to the fault operates, minimizing
disruption to the electrical system.
, IA Master Residential Electrician Exam
Question 6. If a 120V circuit has a 4% voltage drop at the farthest outlet, what is the voltage at that
outlet?
A) 120V
B) 115.2V
C) 124.8V
D) 118.8V
Answer: B
Explanation: 4% of 120V is 4.8V; subtracting this from 120V yields 115.2V at the outlet.
Question 7. In a typical residential service, which component is directly connected to the utility's service
drop?
A) Main panelboard
B) Service entrance conductors
C) Grounding electrode conductor
D) Subpanel
Answer: B
Explanation: The service entrance conductors connect the utility’s service drop to the main service
equipment.
Question 8. According to OSHA, who is responsible for ensuring electrical safety on a residential job site?
A) Only the apprentice
B) The homeowner
C) The employer and qualified person in charge
D) The equipment manufacturer
Answer: C
Explanation: OSHA requires employers and the qualified person in charge to ensure safe work practices
regarding electrical hazards.
Question 9. Which of the following is a correct safety procedure when working near energized
residential service panels?
A) Wear rubber-soled shoes only
B) Work one-handed if possible
C) Assume all conductors are de-energized
D) Disconnect the neutral only
Answer: B
Explanation: Working one-handed reduces the chance of creating a path across the heart in case of
accidental contact.
Question 10. A site-specific electrical safety plan should include:
A) Only a list of tools to be used
B) A detailed risk assessment and control measures
C) The homeowner's phone number only
D) A list of electrical codes
Answer: B
Explanation: A proper safety plan identifies potential hazards and outlines control measures to prevent
accidents.
, IA Master Residential Electrician Exam
Question 11. The purpose of Article 90 in the NEC is to:
A) Provide installation instructions for appliances
B) State the scope and intent of the Code
C) Set pricing for electrical work
D) List all acceptable tools
Answer: B
Explanation: Article 90 covers the purpose, scope, and enforcement of the NEC, ensuring safe electrical
installations.
Question 12. According to Article 100, what does "accessible" mean in the context of electrical
equipment?
A) Reachable only with special tools
B) Capable of being reached quickly without climbing over obstacles
C) Located outdoors
D) Available during daylight hours
Answer: B
Explanation: "Accessible" means equipment can be reached quickly and safely without requiring tools or
climbing.
Question 13. NEC 110.26 requires a minimum depth of working space in front of residential panelboards
of:
A) 24 inches
B) 30 inches
C) 36 inches
D) 48 inches
Answer: C
Explanation: The minimum depth required is 36 inches to provide safe access for maintenance and
emergency situations.
Question 14. Proper identification of branch circuits in a panel is important because:
A) It increases the current-carrying capacity
B) It reduces wiring costs
C) It facilitates safe maintenance and troubleshooting
D) It allows for more outlets per circuit
Answer: C
Explanation: Clear labeling helps electricians and homeowners safely identify circuits for repairs or
modifications.
Question 15. Live parts in a residential electrical system must be guarded to:
A) Save energy
B) Prevent accidental contact and shock hazards
C) Allow more wiring in panels
D) Reduce circuit breaker size
Answer: B
Explanation: Guarding live parts is a critical safety requirement to prevent accidental electric shock.
, IA Master Residential Electrician Exam
Question 16. For installations over 600V affecting residential properties, which is a primary NEC
requirement?
A) Use only aluminum conductors
B) Provide extended working spaces and barriers
C) Install all equipment outdoors
D) Use flexible cords
Answer: B
Explanation: Installations over 600V require additional clearances and barriers to protect workers and
property.
Question 17. In residential branch circuit design, what is the typical ampacity of a general lighting
circuit?
A) 10A
B) 15A
C) 25A
D) 40A
Answer: B
Explanation: General lighting circuits in homes are commonly rated at 15A.
Question 18. According to NEC 210.52, which room in a dwelling must have at least one wall receptacle
outlet?
A) Furnace room
B) Bathroom
C) Attic (unfinished)
D) Closet
Answer: B
Explanation: NEC 210.52 requires bathrooms to have at least one receptacle outlet.
Question 19. Which of the following best describes an AFCI device?
A) Detects ground faults only
B) Detects arc faults to reduce fire hazards
C) Increases voltage to the circuit
D) Reduces circuit resistance
Answer: B
Explanation: AFCIs detect potentially dangerous arcing faults, which can cause fires.
Question 20. The minimum ampacity for a dedicated laundry circuit in a residence is:
A) 10A
B) 15A
C) 20A
D) 30A
Answer: C
Explanation: NEC requires a minimum 20A circuit for laundry equipment.
Question 21. When sizing feeders for a residential subpanel, which factor is MOST important?
A) The length of the feeder run only
B) The color of the insulation
Question 1. In a residential series-parallel circuit, which of the following statements is TRUE?
A) The total resistance is always the sum of all resistances.
B) The total current equals the sum of all branch currents.
C) The voltage across each branch in parallel is different.
D) The current through each series component is different.
Answer: B
Explanation: In a series-parallel circuit, each parallel branch carries its own current, and the total current
is the sum of the branch currents.
Question 2. What is the primary function of a transformer in a residential doorbell system?
A) Increase voltage for long-distance transmission
B) Convert AC to DC
C) Step down voltage to a safer level
D) Reduce current
Answer: C
Explanation: Residential doorbell transformers step down the standard line voltage (120V) to a much
safer voltage (often 16-24V) suitable for doorbell operation.
Question 3. If a residential circuit has a power factor of 0.7, what does this indicate?
A) The circuit is highly efficient
B) The current and voltage are perfectly in phase
C) There is significant reactive power present
D) The load is purely resistive
Answer: C
Explanation: A power factor less than 1 indicates the presence of reactive (non-working) power,
meaning current and voltage are not perfectly in phase.
Question 4. What is the primary reason for calculating available short-circuit current at a residential
panel?
A) To size the conductors
B) To select appropriate overcurrent protection devices
C) To determine lighting load
D) To ground the system
Answer: B
Explanation: Knowing the available short-circuit current helps in selecting circuit breakers or fuses rated
to safely interrupt fault currents.
Question 5. Which statement about protective device coordination is CORRECT for residential systems?
A) Only the main breaker needs to trip during a fault
B) All protective devices should operate simultaneously
C) Downstream breakers should trip before upstream devices
D) Fuses and breakers cannot be used together
Answer: C
Explanation: Proper coordination ensures that only the device closest to the fault operates, minimizing
disruption to the electrical system.
, IA Master Residential Electrician Exam
Question 6. If a 120V circuit has a 4% voltage drop at the farthest outlet, what is the voltage at that
outlet?
A) 120V
B) 115.2V
C) 124.8V
D) 118.8V
Answer: B
Explanation: 4% of 120V is 4.8V; subtracting this from 120V yields 115.2V at the outlet.
Question 7. In a typical residential service, which component is directly connected to the utility's service
drop?
A) Main panelboard
B) Service entrance conductors
C) Grounding electrode conductor
D) Subpanel
Answer: B
Explanation: The service entrance conductors connect the utility’s service drop to the main service
equipment.
Question 8. According to OSHA, who is responsible for ensuring electrical safety on a residential job site?
A) Only the apprentice
B) The homeowner
C) The employer and qualified person in charge
D) The equipment manufacturer
Answer: C
Explanation: OSHA requires employers and the qualified person in charge to ensure safe work practices
regarding electrical hazards.
Question 9. Which of the following is a correct safety procedure when working near energized
residential service panels?
A) Wear rubber-soled shoes only
B) Work one-handed if possible
C) Assume all conductors are de-energized
D) Disconnect the neutral only
Answer: B
Explanation: Working one-handed reduces the chance of creating a path across the heart in case of
accidental contact.
Question 10. A site-specific electrical safety plan should include:
A) Only a list of tools to be used
B) A detailed risk assessment and control measures
C) The homeowner's phone number only
D) A list of electrical codes
Answer: B
Explanation: A proper safety plan identifies potential hazards and outlines control measures to prevent
accidents.
, IA Master Residential Electrician Exam
Question 11. The purpose of Article 90 in the NEC is to:
A) Provide installation instructions for appliances
B) State the scope and intent of the Code
C) Set pricing for electrical work
D) List all acceptable tools
Answer: B
Explanation: Article 90 covers the purpose, scope, and enforcement of the NEC, ensuring safe electrical
installations.
Question 12. According to Article 100, what does "accessible" mean in the context of electrical
equipment?
A) Reachable only with special tools
B) Capable of being reached quickly without climbing over obstacles
C) Located outdoors
D) Available during daylight hours
Answer: B
Explanation: "Accessible" means equipment can be reached quickly and safely without requiring tools or
climbing.
Question 13. NEC 110.26 requires a minimum depth of working space in front of residential panelboards
of:
A) 24 inches
B) 30 inches
C) 36 inches
D) 48 inches
Answer: C
Explanation: The minimum depth required is 36 inches to provide safe access for maintenance and
emergency situations.
Question 14. Proper identification of branch circuits in a panel is important because:
A) It increases the current-carrying capacity
B) It reduces wiring costs
C) It facilitates safe maintenance and troubleshooting
D) It allows for more outlets per circuit
Answer: C
Explanation: Clear labeling helps electricians and homeowners safely identify circuits for repairs or
modifications.
Question 15. Live parts in a residential electrical system must be guarded to:
A) Save energy
B) Prevent accidental contact and shock hazards
C) Allow more wiring in panels
D) Reduce circuit breaker size
Answer: B
Explanation: Guarding live parts is a critical safety requirement to prevent accidental electric shock.
, IA Master Residential Electrician Exam
Question 16. For installations over 600V affecting residential properties, which is a primary NEC
requirement?
A) Use only aluminum conductors
B) Provide extended working spaces and barriers
C) Install all equipment outdoors
D) Use flexible cords
Answer: B
Explanation: Installations over 600V require additional clearances and barriers to protect workers and
property.
Question 17. In residential branch circuit design, what is the typical ampacity of a general lighting
circuit?
A) 10A
B) 15A
C) 25A
D) 40A
Answer: B
Explanation: General lighting circuits in homes are commonly rated at 15A.
Question 18. According to NEC 210.52, which room in a dwelling must have at least one wall receptacle
outlet?
A) Furnace room
B) Bathroom
C) Attic (unfinished)
D) Closet
Answer: B
Explanation: NEC 210.52 requires bathrooms to have at least one receptacle outlet.
Question 19. Which of the following best describes an AFCI device?
A) Detects ground faults only
B) Detects arc faults to reduce fire hazards
C) Increases voltage to the circuit
D) Reduces circuit resistance
Answer: B
Explanation: AFCIs detect potentially dangerous arcing faults, which can cause fires.
Question 20. The minimum ampacity for a dedicated laundry circuit in a residence is:
A) 10A
B) 15A
C) 20A
D) 30A
Answer: C
Explanation: NEC requires a minimum 20A circuit for laundry equipment.
Question 21. When sizing feeders for a residential subpanel, which factor is MOST important?
A) The length of the feeder run only
B) The color of the insulation
