Home Inspector Test Home Inspector Electrical System Safety Hazards 4 — Questions and Answers
Question 1: What is the purpose of an Arc-Fault Circuit Interrupter (AFCI) breaker, and where does NEC require them?
- They prevent shock near water and are required only in bathrooms
- They detect arc-fault signatures and disconnect power, required in bedrooms and most living spaces (Correct answer)
- They protect against overloads only and are required in kitchens
- They replace GFCI protection in all locations
Correct answer: They detect arc-fault signatures and disconnect power, required in bedrooms and most living spaces
AFCI breakers detect the electrical signature of dangerous arcing and trip before a fire starts; NEC requires them in bedrooms and increasingly throughout living areas.
Question 2: An inspector finds a sub-panel in a detached garage with the neutral and ground buses bonded together. What is the issue?
- Sub-panels in detached structures always require bonded buses
- Bonding neutral and ground in a sub-panel creates a parallel neutral path and shock hazard on metal enclosures (Correct answer)
- The bond is required only if the garage is on a separate meter
- There is no issue as long as the main panel also has a bond
Correct answer: Bonding neutral and ground in a sub-panel creates a parallel neutral path and shock hazard on metal enclosures
In a sub-panel, neutral and ground must remain separate; bonding them creates a return current path on grounding conductors and metal enclosures, causing shock risk.
Question 3: What does it indicate when a home inspector finds the panel's main breaker is rated higher than the service entrance wire ampacity?
- The wire is oversized, which improves efficiency
- The service entrance wire can overheat and fail before the breaker trips, creating a fire hazard (Correct answer)
- The main breaker will simply not provide full power
- This configuration is acceptable under NEC for older homes
Correct answer: The service entrance wire can overheat and fail before the breaker trips, creating a fire hazard
The main breaker must be sized to protect the service entrance conductors; an oversized breaker allows the wire to overheat without tripping.
Question 4: An inspector observes flexible armored cable (BX/AC) entering a panel without a proper connector. What is the hazard?
- The cable will carry too much current
- The sharp metal armor edge can cut into wire insulation, causing a short or fire (Correct answer)
- The cable will reduce panel voltage
- The armor prevents proper grounding of the panel
Correct answer: The sharp metal armor edge can cut into wire insulation, causing a short or fire
Without an anti-short bushing and proper connector, the cut metal armor edge can abrade wire insulation over time, creating a fault or fire.
Question 5: A home built in 1965 has ungrounded two-prong outlets throughout. A seller has replaced some with three-prong outlets without rewiring. What should the inspector note?
- Three-prong outlets are safe regardless of whether a ground wire exists
- The added third prong is a false ground unless the circuit was rewired or a GFCI outlet was installed and labeled 'No Equipment Ground' (Correct answer)
- Two-prong outlets must be replaced with three-prong outlets by law
- The seller's upgrade is acceptable if done by a homeowner
Correct answer: The added third prong is a false ground unless the circuit was rewired or a GFCI outlet was installed and labeled 'No Equipment Ground'
Installing a three-prong outlet on an ungrounded circuit creates a false sense of safety unless GFCI protection is added and the outlet labeled as having no equipment ground.
Question 6: What condition is indicated by scorch marks or char around a breaker in the main panel?
- Normal discoloration from age and oxidation
- Evidence of arcing or overheating that poses an immediate fire and shock hazard (Correct answer)
- The breaker was recently reset after a trip
- The panel needs repainting but is otherwise functional
Correct answer: Evidence of arcing or overheating that poses an immediate fire and shock hazard
Char or scorching around a breaker indicates past arcing or sustained overheating, which can damage wiring and panel components and represents a serious fire hazard.
Question 7: Why is a missing knockout slug in an electrical panel a deficiency?
- It reduces the panel's amperage rating
- It allows pests, moisture, and accidental contact with live components inside the panel (Correct answer)
- It voids the breaker warranties
- It prevents proper grounding of the panel enclosure
Correct answer: It allows pests, moisture, and accidental contact with live components inside the panel
Open knockouts expose live bus bars and wiring to moisture, pests, and accidental touch, creating shock and fire risks.
Home Inspector Test Home Inspector Electrical System Safety Hazards 4
What is the purpose of an Arc-Fault Circuit Interrupter (AFCI) breaker, and where does NEC require them?