CSS Electrical Safety and LOTO 3 — Questions and Answers
Question 1: What voltage threshold does OSHA define as 'high voltage' for construction electrical work under 29 CFR 1926?
- Over 50 volts
- Over 120 volts
- Over 600 volts (Correct answer)
- Over 1000 volts
Correct answer: Over 600 volts
OSHA 29 CFR 1926 Subpart K defines high voltage as exceeding 600 volts, which triggers additional safety requirements.
Question 2: According to NFPA 70E, an arc flash hazard analysis must be updated when?
- Every 10 years regardless of changes
- Whenever a major modification or renovation of the electrical system occurs (Correct answer)
- Only after an arc flash incident
- When requested by an employee
Correct answer: Whenever a major modification or renovation of the electrical system occurs
NFPA 70E requires arc flash hazard analysis to be reviewed and updated when a major modification or renovation occurs, or at intervals not exceeding 5 years.
Question 3: What color is OSHA's required safety color for electrical hazard warnings?
- Red
- Orange (Correct answer)
- Yellow
- Green
Correct answer: Orange
Orange is the OSHA-designated safety color for indicating dangerous parts of machines or energized equipment that may cut, crush, shock, or otherwise injure.
Question 4: A qualified electrical worker is defined by OSHA as someone who:
- Holds an electrician's license in the state
- Has at least 5 years of electrical experience
- Has training on hazards and construction or maintenance of electrical equipment they work on (Correct answer)
- Has completed a 30-hour OSHA electrical safety course
Correct answer: Has training on hazards and construction or maintenance of electrical equipment they work on
OSHA defines a qualified person as one who has received training in avoiding electrical hazards and the specific construction/operation of equipment they service.
Question 5: What is the minimum approach distance concept used to protect workers from energized electrical equipment?
- The distance at which PPE is no longer required
- The closest distance a worker may approach energized conductors without additional protection (Correct answer)
- The distance from which rescue operations can begin
- The buffer zone around a transformer vault
Correct answer: The closest distance a worker may approach energized conductors without additional protection
Minimum approach distance (MAD) establishes the closest point a qualified worker may safely approach energized conductors, determined by voltage level.
Question 6: Ground fault circuit interrupters (GFCIs) are required by OSHA on construction sites for which situation?
- All permanent wiring installations
- Receptacle outlets not part of permanent building wiring used in construction (Correct answer)
- Circuits over 240 volts only
- Three-phase power distribution panels
Correct answer: Receptacle outlets not part of permanent building wiring used in construction
OSHA 29 CFR 1926.404 requires GFCI protection for all receptacle outlets that are not part of the permanent building wiring on construction sites.
Question 7: What is the purpose of an 'assured equipment grounding conductor program' as an alternative to GFCI protection?
- To eliminate the need for any grounding on job sites
- To visually inspect and test grounding conductors and equipment on a scheduled basis (Correct answer)
- To certify that equipment meets UL listing requirements
- To document which employees have completed electrical safety training
Correct answer: To visually inspect and test grounding conductors and equipment on a scheduled basis
An assured equipment grounding conductor program uses scheduled visual inspections and continuity/polarity tests to ensure equipment grounding integrity as an alternative to GFCI.
CSS Electrical Safety and LOTO 3
What voltage threshold does OSHA define as 'high voltage' for construction electrical work under 29 CFR 1926?