OSHA Electrical Safety Quiz — 29 CFR 1926.400-449 Practice (Construction) — Page 4 of 4
Free OSHA 30-Hour Construction electrical safety practice test with 40 realistic scenarios. GFCI, AEGCP, temporary wiring, overhead line clearance, lockout/tagout, hazardous locations, and portable generator safety with 29 CFR 1926 Subpart K references. (Page 4 of 4)
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Q31/ 40
A worker notices a GFCI outlet does not trip when the TEST button is pressed. The foreman says 'keep using it — GFCIs are just a backup.' What should happen?
✅ Correct Answer: B
1926.404(b)(1)(i): GFCI protection is mandatory. A GFCI that does not trip when tested is non-functional — the internal sensing circuit or interrupting mechanism has failed. It offers zero protection against ground faults. A non-functional GFCI should be treated as a life-safety emergency.
Q32/ 40
A portable spider box for temporary power is placed directly on the ground outdoors. After 2 inches of overnight rain, the box sits in a puddle. Workers approach to plug in tools. What should have been done?
✅ Correct Answer: A
1926.403(i)(2): electrical equipment shall be installed in accordance with its listing and labeling. If the spider box is not rated NEMA 3R or 4 (weatherproof), it must be protected from weather. Placing an energized electrical distribution box in water is extreme — water can enter the enclosure, energizing the entire puddle. Workers approaching the box could be electrocuted without touching any tool. Spider boxes should be elevated on blocks or hung, and protected by a canopy outdoors.
Q33/ 40
A crew is installing a rooftop HVAC unit. The crane lifting the unit will swing within 15 feet of a 13.8 kV overhead power line. The crane operator says 'we'll just be careful.' What does OSHA require?
✅ Correct Answer: B
1926.1408(a)(1): before beginning operations, the employer must identify if equipment could get closer than 20 feet to a power line. 1926.1408(b): if encroachment is possible, the employer must either de-energize and ground, maintain clearance with encroachment prevention (Option 2), or use an insulating link and range limiter (Option 3). At 13.8 kV, Table A minimum clearance is 10 feet. At 15 feet planned swing distance, the crane is within the 20-foot planning zone — encroachment prevention must be implemented.
Q34/ 40
An extension cord on a construction site has its outer jacket cut, exposing inner conductor insulation but not the copper. The cord is wrapped with electrical tape. Is this acceptable for continued use?
✅ Correct Answer: B
1926.405(a)(2)(ii)(J): extension cords shall be maintained in good condition. 1926.403(a): electrical equipment shall be free from recognized hazards. Tape does not restore original insulation integrity — it can unravel, peel, or allow moisture ingress. OSHA and NEC require damaged cords to be removed from service and either properly spliced using listed devices or replaced. Field taping is not an approved repair method.
Q35/ 40
A building under renovation has existing knob-and-tube wiring (circa 1920) still energized. Workers are demolishing plaster ceilings near this wiring using metal pry bars. The foreman says it's visible and avoidable. What is required?
✅ Correct Answer: B
1926.416(a)(1): no employee shall work in proximity to energized power circuits unless protected. During demolition, accidental contact risk is extremely high. Old knob-and-tube wiring often has brittle, cracked insulation that can fail when disturbed. 1926.416(a)(3): circuits in the work area shall be identified and de-energized before work.
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Q36/ 40
A battery charging station has 6 cordless tool batteries charging via a consumer-grade power strip plugged into an extension cord, placed on a wooden shelf. Is this setup compliant?
✅ Correct Answer: B
1926.403(a): electrical equipment must be approved for the use. Consumer-grade power strips are not listed or approved for construction site use — they lack the durability, weather resistance, and GFCI protection required. 1926.405(a)(2)(ii)(B): temporary wiring shall be installed per approved methods. Chargers should be plugged directly into a job-site electrical box with GFCI protection.
Q37/ 40
A worker is using a handheld grinder marked 'Double Insulated' with a 2-prong plug. The foreman says all tools on site must have 3-prong grounded plugs. Is the foreman correct?
✅ Correct Answer: B
1926.404(f)(4): double-insulated tools are exempt from equipment grounding requirements. The double-insulation system provides two independent layers of electrical insulation. These tools are marked with the international double-insulation symbol (square inside a square). However, they must still be used with GFCI protection on construction sites per 1926.404(b)(1).
Q38/ 40
During an OSHA inspection, the compliance officer notices the AEGCP log has missing entries and the last continuity test was 4 months ago. The program document is a single handwritten page. Is this AEGCP compliant?
✅ Correct Answer: B
1926.404(b)(1)(iii): the AEGCP must be in writing, designate a competent person, include daily visual inspection, require continuity testing at intervals not exceeding 3 months (plus before first use and after repair), and document all tests. A 4-month gap and a single informal page lacking program procedures do not meet the requirements.
Q39/ 40
A worker is using an electric chainsaw to cut tree limbs while standing on an aluminum extension ladder at 15 feet. The power cord runs from the house, across wet grass, to the ladder. What are the electrical violations?
✅ Correct Answer: B
1926.416(a)(1): employees working near energized circuits must be protected. 1926.404(b)(1): GFCI protection required. The aluminum ladder creates a direct path to ground — if the saw malfunctions or cord is damaged, the worker WILL be electrocuted. The wet grass reduces ground resistance. OSHA strongly discourages power tool use from ladders.
Q40/ 40
A construction crew is using a portable generator to power tools in a trench. The generator is placed 10 feet from the trench edge on dry ground. Workers complain of mild tingling when touching the metal case of a drill. What is the most likely cause?
✅ Correct Answer: B
1926.404(b)(1)(i) requires that all 120-volt, single-phase, 15- and 20-ampere receptacle outlets on construction sites that are not part of the permanent wiring have approved ground-fault circuit interrupters (GFCIs) for personnel protection. The tingling sensation indicates leakage current finding a path to ground through the worker — a classic ground fault condition. 1926.404(f)(3) requires the generator's frame to be grounded if it supplies cord-and-plug connected equipment. A properly functioning GFCI would trip at 5mA (±1mA), well below the perception threshold.