Home Inspector Electrical Practice Test - 20 Questions
1. In a typical 120/240-volt residential electrical service, the voltage measured between the two ungrounded service conductors should be approximately:
A. 60 volts
B. 120 volts
C. 208 volts
D. 240 volts
2. At the main service disconnect, the grounded (neutral) conductor is generally:
A. Isolated from the equipment grounding system
B. Bonded to the service enclosure and grounding system
C. Connected only to branch-circuit neutrals
D. Connected directly to the water heater
3. In a subpanel downstream from the service disconnect, the neutral bus should generally be:
A. Bonded to the panel enclosure
B. Connected to the grounding bus with a bonding screw
C. Isolated from the panel enclosure and equipment grounding bus
D. Removed if a grounding conductor is present
4. An inspector finds two branch-circuit conductors connected to a breaker terminal designed for only one conductor. This condition is commonly called:
A. Double tapping
B. Double bonding
C. Backfeeding
D. Parallel grounding
5. The primary purpose of a circuit breaker is to:
A. Protect people from all electrical shocks
B. Protect conductors from excessive current
C. Maintain constant voltage
D. Provide grounding for the circuit
6. Which conductor size is generally associated with a 15-amp residential copper branch circuit?
A. 10 AWG
B. 12 AWG
C. 14 AWG
D. 16 AWG
7. An inspector observes 14 AWG copper conductors connected to a 20-amp breaker on a typical branch circuit. What is the primary concern?
A. The breaker may not adequately protect the conductors from overheating
B. The circuit will operate at 240 volts
C. The receptacles will have reversed polarity
D. The grounding electrode will become energized
8. What is the primary purpose of GFCI protection?
A. Protect wiring from overload
B. Reduce the risk of electrical shock
C. Protect appliances from power surges
D. Detect excessive voltage
9. What is the primary purpose of AFCI protection?
A. Detect dangerous electrical arcing conditions
B. Detect plumbing leaks
C. Prevent electrical shock from ground faults only
D. Protect the service from lightning
10. A three-slot receptacle tests as having an open ground. This means:
A. The neutral is carrying too much current
B. The equipment grounding path is incomplete
C. Hot and neutral are necessarily reversed
D. The circuit has no voltage
11. Which condition inside an electrical panel represents the MOST immediate safety concern?
A. Poorly written circuit directory
B. Dust on the bottom of the enclosure
C. Accessible exposed energized components
D. Several different wire colors
12. What is the purpose of the grounding electrode system at a residential electrical service?
A. Carry normal branch-circuit current back to the utility
B. Connect the electrical system to earth and help stabilize system voltage relative to ground
C. Replace equipment grounding conductors
D. Prevent circuit breakers from tripping
13. A white insulated conductor being used as an ungrounded conductor should generally be:
A. Removed
B. Reidentified as an ungrounded conductor where required
C. Connected to the grounding bus
D. Connected to the neutral bus at both ends
14. Which condition is commonly associated with older aluminum branch-circuit wiring?
A. Connections may overheat when improperly terminated or maintained
B. Aluminum cannot conduct electricity
C. Aluminum wiring always requires a 30-amp breaker
D. Aluminum wiring cannot be grounded
15. What is reversed polarity at a standard 120-volt receptacle?
A. The equipment ground is too large
B. The hot and neutral conductors are connected to the opposite terminals
C. Two hot conductors are connected together
D. The receptacle is supplied by 240 volts
16. An inspector removes a panel cover and observes rust and water staining inside the electrical panel. What is the BEST course of action?
A. Ignore it if the breakers operate
B. Report the moisture intrusion and recommend correction/evaluation
C. Spray the panel with a corrosion inhibitor
D. Tighten all breaker connections
17. Why is a missing knockout cover in an electrical panel a concern?
A. It reduces available amperage
B. It can allow accidental access to energized components
C. It causes reversed polarity
D. It prevents breakers from tripping
18. Which of the following is MOST indicative of overheating at an electrical connection?
A. A handwritten circuit directory
B. Discoloration, melted insulation, or charring
C. A white neutral conductor
D. A plastic panel directory
19. An inspector finds a three-prong receptacle installed on an older two-wire circuit with no equipment grounding conductor. Which statement is MOST accurate?
A. A three-prong receptacle automatically provides grounding
B. The receptacle may create the appearance of grounding when an equipment grounding path is absent
C. The circuit automatically becomes 240 volts
D. The receptacle cannot operate without a ground
20. While inspecting the service panel, the inspector notices that several neutral and equipment grounding conductors share terminals. The inspector should FIRST determine:
A. Whether the panel is the service equipment or a downstream panel
B. Whether the house has copper plumbing
C. Whether AFCI breakers are installed
D. Whether the receptacles are tamper-resistant