Domain 1, task 5
Electrical practice questions
10 free electrical questions in the style of the National Home Inspector Exam, each with the answer and the reason. The official outline calls this task "Electrical" and gives it 7% of the exam, about 12 of the 175 scored questions.
Checked on October 4, 2026
Question 1 of 10
A home inspector traces the circuit serving a 240 volt water heater. This circuit is:
The answer is DA water heater at 240 volts is one of the loads specifically excluded, and the condensers of air conditioners and of heat pumps are the others. There is no neutral in those circuits for two energized conductors to share. A feeder supplies another panelboard, which is not what a water heater circuit does.
Question 2 of 10
A ufer grounding electrode serves a 200 amp service. The grounding electrode conductor must be copper of what size?
The answer is BA ufer electrode at 200 amps or above calls for #4 AWG copper. The general floor once a service reaches 150 amps is #6 AWG copper, and a service of 125 amps or less may drop to #8 AWG copper. Of the three rules, the ufer rule is the strictest.
Question 3 of 10
A home inspector finds corrugated stainless steel gas tubing with no bonding connection anywhere on it. Where should that bond have been made?
The answer is AThe bond belongs on the gas piping, at the first metal pipe or the first metal fitting past the meter, and tubing carrying no bond at all is a listed defect. An electrode, the appliance at the far end, and the point of entry through the foundation are each the wrong place.
Question 4 of 10
What condition has to exist before an arcing fault can occur?
The answer is BAn arcing fault starts with damage: a conductor or its insulation is injured, and sparks then jump between conductors or along a single conductor. A conductor carrying too much current is an overcurrent, which a plain breaker or fuse already handles without any AFCI involved.
Question 5 of 10
Which standard covers the panelboard ampacity rating, circuit identification, and the one neutral per lug rule?
The answer is AThree subjects sit in E3706: the ampacity rating, the marking of circuits, and the single neutral in a lug. E3902 sets out where AFCI and GFCI protection goes, E3907 covers cabinet and panelboard installation generally, and E3607.2 governs where a grounding electrode conductor may be connected.
Question 6 of 10
Service entrance cable may not be buried. Which cable may be?
The answer is CThe contrast is direct: SE may not be buried, and USE may. NM is closed to burial for the same reason AC is, since a buried raceway counts as a wet location.
Question 7 of 10
How should each knob and tube wire enter a junction box?
The answer is BOne conductor, one opening, one bushing. The clamped opening is the NM requirement, and NM also has to be fastened within 12 inches of the box it enters.
Question 8 of 10
A kitchen island measures 30 inches long and 14 inches wide. Does it require a receptacle?
The answer is AAn island needs a receptacle once its length passes 2 feet and its width passes 1 foot. At 30 inches by 14 inches it passes both thresholds. The same pair of dimensions governs a peninsula, with the length taken from the perpendicular wall nearest it.
Question 9 of 10
Besides the switch and the receptacle, what else at a device location connects to the equipment grounding conductor?
The answer is DFour metal parts tie back to the EGC at a device: the switch, the receptacle, the metal box, and the metal face plate. The plate usually gets there through the screws that fasten it to the device, so the screws are the path rather than a part on the list.
Question 10 of 10
A new house has no attached garage, all electric appliances, and one gas fireplace. Is a carbon monoxide alarm required?
The answer is COne carbon monoxide alarm at minimum goes into a new house holding a fuel-burning appliance, and the manual counts a fireplace as one of those. An attached garage is a second trigger rather than the only one.
Pick an answer to see the reason
What the outline puts in this task
- The service, from the drop or lateral to the grounding
- Panels and subpanels, breakers, GFCI and AFCI protection, and known problem panels
- Wiring methods, from NM cable to knob and tube
- Outlets, switches, and fixtures
- Solar, wind, and generator systems
- Electric vehicle charging equipment
These questions come from the course question bank and are set aside for free use. None of them is on a paid practice exam. See all 19 topics.
See where you stand
Take a free 200 question practice exam, weighted like the NHIE, with your score by task.
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