OSHA - Safety Certificate Electrical Safety Standards Questions and Answers 1 — Questions and Answers
Question 1: According to OSHA 29 CFR 1910.303(g)(2), live parts of electric equipment operating at what minimum voltage must be guarded against accidental contact?
- 120 volts AC
- 30 volts AC or DC
- 50 volts AC or DC (Correct answer)
- 240 volts AC
Correct answer: 50 volts AC or DC
OSHA standard 29 CFR 1910.303(g)(2)(i) explicitly states, 'live parts of electric equipment operating at 50 volts or more shall be guarded against accidental contact.' This rule applies to both AC and DC voltages.
Question 2: A maintenance worker is preparing to perform service on a piece of machinery. The energy isolating device is capable of being locked out. According to OSHA's Lockout/Tagout standard (29 CFR 1910.147), which of the following is the required practice?
- The employer can choose between using a lockout device or a tagout system.
- A tagout system is sufficient if the employee is trained on its meaning.
- The energy isolating device must be locked out; tagout can only be used if the device cannot be locked. (Correct answer)
- A tagout system must be used in conjunction with a lockout device.
Correct answer: The energy isolating device must be locked out; tagout can only be used if the device cannot be locked.
The standard at 29 CFR 1910.147(c)(2)(i) mandates that if an energy isolating device is capable of being locked out, the employer's energy control program must utilize lockout. A tagout system is only permitted as an alternative if the device is not capable of being locked out and the employer can demonstrate that the tagout system provides equivalent employee protection.
Question 3: On a construction site, which of the following is an acceptable method for protecting employees from ground-fault hazards when using portable electric tools and cord sets?
- Using only double-insulated tools.
- Implementing an Assured Equipment Grounding Conductor Program (AEGCP). (Correct answer)
- Visually inspecting all cords and tools before each use.
- Requiring all employees to wear rubber-soled boots.
Correct answer: Implementing an Assured Equipment Grounding Conductor Program (AEGCP).
According to 29 CFR 1926.404(b)(1)(i), employers must use either ground-fault circuit interrupters (GFCIs) or an Assured Equipment Grounding Conductor Program (AEGCP) to protect employees on construction sites. While visual inspections and using proper PPE are important safety practices, they are not substitutes for these specific ground-fault protection requirements.
Question 4: A qualified electrician is running a temporary extension cord to power a piece of equipment in a general industry setting. Which of the following uses of the flexible cord is prohibited under OSHA 29 CFR 1910.305(g)?
- Running the cord through a doorway, provided it is protected from damage.
- Connecting the cord to a pendant for temporary lighting.
- Using the cord as a substitute for the fixed wiring of the structure. (Correct answer)
- Powering a portable tool or appliance.
Correct answer: Using the cord as a substitute for the fixed wiring of the structure.
OSHA standard 29 CFR 1910.305(g)(1)(iv)(A) explicitly prohibits the use of flexible cords and cables as a substitute for the fixed wiring of a structure. The other options are generally permissible uses for flexible cords under specific conditions outlined in the standard.
Question 5: A crane is operating on a construction site near an overhead power line with a voltage of 50 kV. According to OSHA 29 CFR 1926.1408, what is the absolute minimum approach distance that must be maintained from the line if it is not de-energized?
- 5 feet
- 25 feet
- 15 feet
- 20 feet (Correct answer)
Correct answer: 20 feet
For voltages from over 350V up to 50kV, OSHA's Table A in 29 CFR 1926.1408 specifies a minimum clearance distance of 10 feet. However, the standard provides an option to maintain a 20-foot clearance for lines up to 350 kV as a simpler, more protective measure without needing to determine the precise voltage. In the absence of de-energizing, ensuring no part of the equipment gets closer than 20 feet is a key compliance option.
Question 6: An employer implements an Assured Equipment Grounding Conductor Program (AEGCP) on a construction site. Which of the following is a key requirement of this program?
- All cord sets and receptacles must be tested for continuity and correct terminal connection at least every 6 months.
- A written description of the program must be kept at the jobsite. (Correct answer)
- Only a certified electrician is permitted to conduct the required tests.
- The program eliminates the need for any visual inspections of equipment.
Correct answer: A written description of the program must be kept at the jobsite.
OSHA standard 1926.404(b)(1)(iii) requires that a written description of the Assured Equipment Grounding Conductor Program, including the specific procedures adopted, be kept at the jobsite for inspection and for reference by employees.
OSHA - Safety Certificate Electrical Safety Standards Questions and Answers 1
According to OSHA 29 CFR 1910.303(g)(2), live parts of electric equipment operating at what minimum voltage must be guarded against accidental contact?