CHST CHST - Construction Health and Safety Technician Electrical Safety and LOTO Questions and Answers 4 — Questions and Answers
Question 1: A GFCI trips repeatedly when a power tool is plugged in on a construction site. What is the safest immediate action?
- Reset the GFCI and continue using the tool
- Bypass the GFCI with an extension cord to a standard outlet
- Remove the tool from service and have it inspected/repaired (Correct answer)
- Increase the circuit breaker amperage to prevent future trips
Correct answer: Remove the tool from service and have it inspected/repaired
Repeated GFCI tripping indicates a ground fault in the tool; it must be removed from service and inspected by a qualified person before further use.
Question 2: What is the correct sequence for re-energizing equipment after LOTO maintenance is complete?
- Remove locks → notify affected employees → re-energize → remove tags
- Inspect work area → notify affected employees → remove each worker's lock → re-energize (Correct answer)
- Re-energize → verify function → remove locks → notify employees
- Remove tags → verify tools cleared → re-energize → update LOTO log
Correct answer: Inspect work area → notify affected employees → remove each worker's lock → re-energize
The proper sequence is: ensure all tools/workers are clear, notify affected employees, have each authorized worker remove their own lock, then restore energy.
Question 3: Which condition makes using tagout instead of lockout acceptable under 29 CFR 1910.147?
- The energy source is electrical rather than mechanical
- The energy-isolating device is not capable of being locked out and the employer can demonstrate equal protection (Correct answer)
- The work will take less than 15 minutes
- The task is performed by a qualified electrician
Correct answer: The energy-isolating device is not capable of being locked out and the employer can demonstrate equal protection
Tagout alone is permitted only when the energy-isolating device cannot physically accept a lock AND the employer provides equivalent protection through additional means.
Question 4: Under OSHA 29 CFR 1926.403, what is the maximum allowable voltage for flexible cords used with portable tools on construction sites without additional overcurrent protection?
- 120 volts
- 240 volts
- The standard does not set a voltage limit for flexible cords (Correct answer)
- 600 volts with proper insulation rating
Correct answer: The standard does not set a voltage limit for flexible cords
OSHA 1926.403 addresses conductor use and protection requirements but does not set a specific voltage ceiling for flexible cords; insulation and rating requirements apply based on application.
Question 5: An electrical arc flash incident on a construction site results in second-degree burns to a worker wearing standard work clothes. Which NFPA 70E concept was most likely neglected?
- Ground fault circuit interrupter testing
- Arc flash hazard analysis and appropriate arc-rated PPE selection (Correct answer)
- Lockout/tagout verification
- Equipment labeling requirements
Correct answer: Arc flash hazard analysis and appropriate arc-rated PPE selection
Arc-rated PPE matched to the incident energy level from a site-specific arc flash hazard analysis would have reduced burn severity even when arc flash occurs.
Question 6: Which OSHA construction standard governs electrical safety requirements specifically for the construction industry, as distinct from general industry?
- 29 CFR 1910.301–399
- 29 CFR 1926.400–449 (Correct answer)
- 29 CFR 1910.147
- 29 CFR 1926.502
Correct answer: 29 CFR 1926.400–449
Subpart K (29 CFR 1926.400–449) of OSHA's construction standards covers electrical safety requirements specific to construction activities.
Question 7: What does the term 'qualified person' mean in the context of OSHA's electrical safety standards?
- Any employee who has completed a 10-hour OSHA construction safety course
- A person trained and knowledgeable in electrical hazards and authorized to work on or near energized equipment (Correct answer)
- A licensed electrician with at least 5 years of experience
- An employee certified by a third-party electrical safety organization
Correct answer: A person trained and knowledgeable in electrical hazards and authorized to work on or near energized equipment
OSHA defines a qualified person as one who has received training on electrical hazards and the skills to distinguish exposed live parts and determine their nominal voltage.
CHST CHST - Construction Health and Safety Technician Electrical Safety and LOTO Questions and Answers 4
A GFCI trips repeatedly when a power tool is plugged in on a construction site.
What is the safest immediate action?