PC OSHA Safety Standards 3 — Questions and Answers
Question 1: Under OSHA 29 CFR 1926.403(i), what is the maximum voltage permitted for temporary lighting used on construction sites without special guarding?
- 120V (Correct answer)
- 240V
- 277V
- 480V
Correct answer: 120V
Temporary lighting on construction sites must not exceed 120V unless the luminaire is protected from breakage.
Question 2: OSHA defines an 'authorized employee' under the lockout/tagout standard as someone who:
- Has been trained to recognize hazardous energy sources
- Locks out or tags out machines to perform servicing or maintenance (Correct answer)
- Works in the same area as the equipment being serviced
- Has been employed for more than 90 days
Correct answer: Locks out or tags out machines to perform servicing or maintenance
An authorized employee is the worker who actually applies the lockout/tagout device to control hazardous energy.
Question 3: When using a scaffolding system near energized power lines, OSHA 29 CFR 1926.451 requires scaffolds to be erected at least how far from lines rated 300V to 50kV?
- 3 feet
- 5 feet
- 10 feet (Correct answer)
- 15 feet
Correct answer: 10 feet
Scaffolds must be kept at least 10 feet from power lines rated between 300V and 50kV per OSHA's scaffold standard.
Question 4: An electrician is exposed to a substance listed as an OSHA-regulated carcinogen. Per 29 CFR 1910.1003, what is the minimum retention period for exposure records?
- 5 years
- 10 years
- 30 years (Correct answer)
- 40 years
Correct answer: 30 years
OSHA requires employee exposure records for regulated carcinogens to be retained for at least 30 years.
Question 5: Under OSHA's ground fault protection requirements for construction (29 CFR 1926.404(b)), which device must be used on all 120V, 15A and 20A temporary receptacle circuits?
- Arc fault circuit interrupter (AFCI)
- Ground fault circuit interrupter (GFCI) (Correct answer)
- Thermal magnetic breaker
- Residual current device rated 100mA
Correct answer: Ground fault circuit interrupter (GFCI)
OSHA requires GFCI protection on all 120V, single-phase, 15A and 20A temporary power outlets at construction sites.
Question 6: What is the OSHA-required minimum width of access and egress for electrical equipment rooms containing equipment rated over 1200A and over 6 feet wide?
- 24 inches
- 30 inches
- 36 inches (Correct answer)
- 42 inches
Correct answer: 36 inches
OSHA (and NEC 110.26) requires a minimum 36-inch working space clearance in front of high-amperage electrical equipment.
Question 7: Per OSHA 29 CFR 1926.417, which action is required after a worker locks out equipment and before beginning work?
- Notify the facility safety officer in writing
- Attempt to operate the equipment to verify de-energization (Correct answer)
- Post a danger sign near the equipment
- Have a second worker verify the lockout tag
Correct answer: Attempt to operate the equipment to verify de-energization
OSHA requires workers to attempt to operate the equipment's normal controls after lockout to verify that it is actually de-energized.
PC OSHA Safety Standards 3
Under OSHA 29 CFR 1926.403(i), what is the maximum voltage permitted for temporary lighting used on construction sites without special guarding?