TheoryHome Inspector
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30 free Home Inspector questions
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Electrical Systems
What is the minimum clearance required between the service drop conductors and the roof surface over which they pass (where the roof pitch is less than 4 in 12)?
Correct — A. NEC 230.24 requires at least 8 feet of clearance above a roof surface for service conductors where the pitch is less than 4/12. Steeper pitches allow a reduced 3-foot clearance. -
Electrical Systems
The weatherhead (service entrance head) for overhead service conductors must be located at or above which point relative to the service equipment?
Correct — C. The weatherhead must be positioned at the top of the service entrance so that the drip loop directs water away and the conductors enter from above, preventing water infiltration. -
Electrical Systems
A residential service entrance conductor must maintain a minimum clearance above a public sidewalk or walkway of:
Correct — B. NEC 230.24(B) requires service conductors to maintain at least 10 feet of clearance above walkways accessible only to pedestrians, ensuring pedestrian safety beneath the wires. -
Electrical Systems
When inspecting a service entrance, a home inspector finds that the service entrance cable is stapled directly to the wood framing inside the wall cavity without protection. This is a concern because:
Correct — D. Service entrance cable in accessible locations must be protected from physical damage. Unprotected cable is subject to nail punctures and abrasion, which can compromise the insulation and create hazards. -
Electrical Systems
A 200-amp residential service requires copper service entrance conductors of at least which AWG size?
Correct — A. NEC Table 310.12 permits 2/0 AWG copper conductors for a 200-amp residential service. Aluminum would require 4/0 AWG for the same rating, reflecting aluminum's lower conductivity. -
Electrical Systems
What is the primary purpose of a grounding electrode system at a residence?
Correct — B. The grounding electrode system connects the electrical system to earth to stabilize system voltage and provide a path to dissipate lightning and utility surge energy, protecting equipment and occupants. -
Electrical Systems
Which of the following is a recognized grounding electrode under the NEC?
Correct — C. A concrete-encased electrode (Ufer ground) — 20 feet or more of rebar in a concrete foundation — is a recognized NEC grounding electrode. Aluminum rods are not permitted, and plastic pipe is not conductive. -
Electrical Systems
Bonding of metal gas piping to the electrical system is required because:
Correct — D. Metal gas piping that is not bonded to the electrical system can accumulate a voltage potential. Bonding equalizes potential and prevents arcing near gas piping, which could ignite leaking gas. -
Electrical Systems
A ground rod used as a grounding electrode must be driven to a minimum depth of:
Correct — A. NEC 250.52(A)(5) requires driven ground rods to be installed to a minimum depth of 8 feet to ensure adequate soil contact and effective grounding. -
Electrical Systems
At a service panel, the neutral bar and the equipment grounding bar must be bonded together. In a subpanel fed from the main panel, this bonding strap should be:
Correct — B. In a subpanel (remote distribution panel), the neutral must be kept isolated from the equipment grounding conductors. The main panel is the only place where the neutral-to-ground bond is made, preventing parallel neutral current paths through the grounding system. -
Electrical Systems
A home inspector observes that the metallic water supply piping does not extend at least 10 feet into the earth. According to the NEC, this means:
Correct — C. NEC 250.52(A)(1) allows interior metal water piping as a grounding electrode only when it is electrically continuous and in contact with the earth for at least 10 feet. If it is not, a supplemental electrode is required. -
Electrical Systems
What is the maximum number of overcurrent devices (circuit breakers) permitted in a residential panelboard?
Correct — D. The maximum number of overcurrent devices is determined by the panel's listing and label. Modern NEC editions removed the old '42-circuit' rule; the panel label (e.g., 'Maximum 40 circuits') governs. -
Electrical Systems
A home inspector finds a Federal Pacific Electric (FPE) Stab-Lok panel. The correct reporting approach is to:
Correct — B. FPE Stab-Lok panels have documented reliability concerns including failure to trip under overload. Home inspectors should note this as a safety concern and recommend further evaluation by a qualified electrician, without performing electrical testing themselves. -
Electrical Systems
Unused knockout openings in an electrical panel must be:
Correct — C. NEC 408.7 requires all unused openings in panelboards to be effectively closed to prevent foreign objects or accidental contact with live parts, using listed closures designed for that purpose. -
Electrical Systems
A 240-volt, 2-pole breaker in a panel is supplying a circuit, but the inspector notices the breaker handle is not tied together. What is the concern?
Correct — A. Two-pole breakers for 240-volt circuits must have their handles tied so that a fault on either pole trips both simultaneously. An un-tied pair could leave one 120-volt leg energized after a fault, creating a shock hazard. -
Electrical Systems
During an inspection, a home inspector observes that the service panel is installed in a bathroom. Under the NEC, this installation is:
Correct — D. NEC 240.24(E) prohibits overcurrent devices (including panelboards) from being located in bathrooms due to the risk of shock in a wet environment. This applies to both main panels and subpanels. -
Electrical Systems
A standard 15-amp household branch circuit is typically wired with which wire gauge?
Correct — B. 14 AWG copper wire has an ampacity of 15 amps when protected by a 15-amp breaker. A 20-amp circuit requires 12 AWG, and a 30-amp circuit typically uses 10 AWG. -
Electrical Systems
Which of the following is typically a 240-volt dedicated circuit in a home?
Correct — C. Electric clothes dryers require 240 volts and typically a 30-amp dedicated circuit (NEMA 10-30 or 14-30 outlet). Most kitchen appliances and lighting circuits operate on 120 volts. -
Electrical Systems
The National Electrical Code requires at least two 20-amp small appliance branch circuits in a kitchen. These circuits must serve:
Correct — A. NEC 210.11(C)(1) requires a minimum of two 20-amp small appliance circuits that serve only the receptacles in the kitchen, pantry, breakfast room, and dining room countertop areas—not other areas of the home. -
Electrical Systems
A dedicated 20-amp laundry branch circuit is required by the NEC to serve:
Correct — D. NEC 210.11(C)(2) requires one 20-amp dedicated circuit for laundry receptacles. This circuit must serve only laundry area receptacles to ensure the washer has adequate power without sharing with other loads. -
Electrical Systems
A home inspector finds that a 20-amp breaker is protecting a circuit wired with 14 AWG wire. This is a defect because:
Correct — B. Overcurrent protection must be sized to protect the wiring. A 20-amp breaker allows twice the safe ampacity of 14 AWG wire (15A) to flow before tripping, risking insulation overheating and fire. -
Electrical Systems
The NEC limits the continuous load on a branch circuit to what percentage of the circuit's ampere rating?
Correct — C. NEC 210.20 limits continuous loads (lasting 3 or more hours) to 80% of the branch circuit's rating. This prevents conductors and overcurrent devices from operating at their maximum rated temperature for extended periods. -
Electrical Systems
GFCI protection is required for all receptacles in a bathroom. What does GFCI stand for?
Correct — A. GFCI stands for Ground Fault Circuit Interrupter. It monitors current balance and trips within milliseconds when it detects as little as 5 milliamps of leakage to ground, protecting against electrocution in wet locations. -
Electrical Systems
According to the NEC, GFCI protection is required for receptacles located within how many feet of a kitchen sink?
Correct — D. NEC 210.8(A)(6) requires GFCI protection for all kitchen receptacles that serve the countertop surfaces, and specifically those within 6 feet of a kitchen sink, because of the proximity to water. -
Electrical Systems
A home inspector tests a GFCI receptacle using a plug-in tester and the TEST button trips it, but the outlet does not lose power. This indicates:
Correct — B. A GFCI that trips (indicator changes) but still passes power is wired with the line and load connections reversed (back-wired incorrectly) or is internally defective—it will not protect against ground faults in either case. -
Electrical Systems
GFCI protection is required for all 15- and 20-amp receptacles installed in which of the following locations?
Correct — C. NEC 210.8(A)(2) requires GFCI protection for garage receptacles and structures with floors at or below grade level, because these locations are prone to moisture and ground fault hazards. -
Electrical Systems
A home built in 1975 does not have GFCI protection in the bathrooms. As a home inspector, you should:
Correct — A. Home inspectors report on current safety standards, not just whether something met the code when built. While the installation may have been code-compliant at the time, the absence of GFCI protection in a bathroom is a recognized safety concern that should be noted and an upgrade recommended. -
Electrical Systems
An outdoor receptacle installed under a covered patio — not directly exposed to rain — still requires GFCI protection because:
Correct — D. The NEC requires GFCI protection for all outdoor receptacles on residential structures, whether or not they are sheltered from direct rain. Moisture, humidity, and extension cords still create shock hazards in covered outdoor areas. -
Electrical Systems
What type of hazard does an Arc Fault Circuit Interrupter (AFCI) breaker protect against?
Correct — B. AFCIs detect the unique electrical signature of arcing faults—often from damaged cords or loose connections—and disconnect the circuit before the arc can ignite surrounding materials. GFCIs protect against shock; AFCIs protect against arc-ignited fires. -
Electrical Systems
Under modern NEC editions, AFCI protection is required for circuits supplying which of the following rooms in a dwelling?
Correct — A. The NEC has expanded AFCI requirements over successive editions to include virtually all circuits in habitable spaces of a dwelling, starting with bedrooms in 1999 and now including living areas, hallways, and more. The bedroom was the historic starting point.
Home Inspector sample questions
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Electrical Systems An AFCI breaker is found in the panel but keeps nuisance-tripping on a bedroom circuit. The most likely cause is:
A. The bedroom has too many light fixtures
B. The circuit is on a 15-amp breaker instead of 20-amp
C. A damaged extension cord, loose connection, or defective device on the circuit is generating an arcing signature ✓
D. The circuit is too long, causing excessive voltage drop
Correct — C. AFCIs are designed to trip on arcing signatures. Nuisance tripping usually indicates the AFCI is detecting a real arc from a defective cord, loose wiring device connection, or failing appliance—conditions that warrant investigation.
Home Inspector When inspecting a main electrical panel, double-tapped breakers (two conductors under one breaker terminal) are generally considered a defect unless:
A. The breaker is listed for two conductors by the manufacturer ✓
B. The panel is rated 200 amps or more
C. Both conductors are the same gauge
D. The circuit is a dedicated 20-amp circuit
Correct — A. Most circuit breakers are only listed for one conductor per terminal. Double-tapping with a breaker not rated for it can cause loose connections, overheating, and nuisance tripping. Only breakers specifically listed (by the manufacturer) for dual conductors are acceptable.
HVAC Systems A high-efficiency condensing furnace is identified by which characteristic?
A. A single-pipe flue vented through the roof
B. A barometric damper on the flue
C. A PVC vent pipe rather than a metal flue ✓
D. A standing pilot light
Correct — C. Condensing furnaces extract so much heat that the flue gases cool below the dew point; the resulting condensate requires corrosion-resistant PVC venting rather than metal flue pipe. This is the field identifier for AFUE ≥ 90% units.
Interior, Insulation & Ventilation What does the 'R-value' of insulation measure?
A. The weight per square foot of the insulation material
B. The moisture resistance of the insulation
C. The thermal resistance to heat flow ✓
D. The fire rating of the insulation product
Correct — C. R-value measures thermal resistance — the higher the R-value, the greater the insulation's ability to resist heat flow. It does not measure weight, moisture, or fire resistance.
Plumbing Systems Which pipe material is identified by its blue color and is commonly used for cold-water supply lines?
A. PEX-B ✓
B. CPVC
C. Galvanized steel
D. Cast iron
Correct — A. PEX (cross-linked polyethylene) tubing is color-coded: blue for cold water and red for hot water. CPVC is cream/white and used for hot and cold supply; galvanized and cast iron are not color-coded blue.
Reporting & Safety Which format must a home inspection report use to clearly separate each inspected system or component?
A. Organized sections for each system with clearly labeled components ✓
B. A single continuous narrative paragraph covering all systems
C. A handwritten checklist provided only upon request
D. An oral summary delivered after the inspection is completed
Correct — A. Home inspection standards of practice require reports to be organized with distinct sections for each system. This allows clients and agents to easily locate information about specific components.
Roofing & Exterior What is the minimum overlap (headlap) recommended for standard 3-tab asphalt shingles on a roof with a 4:12 pitch?
A. 2 inches ✓
B. 1 inch
C. 4 inches
D. 6 inches
Correct — A. Standard 3-tab asphalt shingles require a minimum 2-inch headlap on roofs with a 4:12 or steeper pitch to ensure water cannot penetrate the underlying course. Manufacturer instructions typically specify this minimum.
Standards of Practice & Ethics A home inspection is primarily defined as which of the following?
A. A visual examination of the readily accessible systems and components of a home ✓
B. A code compliance inspection of all building systems
C. A guarantee of the current and future condition of the home
D. An appraisal of the home's market value
Correct — A. A home inspection is a visual examination of the readily accessible installed systems and components of a home. It is not a code inspection, appraisal, or guarantee of condition.
About the Home Inspector test
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Roofing & Exterior, Structure & Foundation, Electrical Systems, Plumbing Systems, HVAC Systems, Interior, Insulation & Ventilation — and more.
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You will be tested on
- Work health & safety law and duty of care
- Spotting site hazards and controlling risk
- Personal protective equipment (PPE)
- Emergency procedures and incident reporting
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Topics in this question bank
Work health & safety law and duty of care
Spotting site hazards and controlling risk
Personal protective equipment (PPE)
Emergency procedures and incident reporting
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