IEC Electrical Safety Practices 2 — Questions and Answers
Question 1: When working on energized electrical equipment, which OSHA standard specifically governs electrical safety for general industry?
- 29 CFR 1910.333 (Correct answer)
- 29 CFR 1926.416
- 29 CFR 1910.147
- 29 CFR 1926.404
Correct answer: 29 CFR 1910.333
OSHA 29 CFR 1910.333 covers safety requirements for working on or near live parts in general industry electrical installations.
Question 2: What is the minimum approach distance for a qualified worker working on uninsulated 4kV conductors?
- 1 foot 5 inches
- 2 feet 2 inches (Correct answer)
- 3 feet 6 inches
- 5 feet 3 inches
Correct answer: 2 feet 2 inches
NFPA 70E Table 130.4(D)(a) specifies a minimum approach distance of 2 feet 2 inches for uninsulated conductors at 4.0 kV.
Question 3: Which type of glove is rated for use on circuits up to 26,500 volts AC?
- Class 00
- Class 1
- Class 2 (Correct answer)
- Class 3
Correct answer: Class 2
Class 2 rubber insulating gloves are rated for use on circuits up to 17,000 volts AC (proof-tested to 20,000V), while Class 3 covers up to 26,500V.
Question 4: An arc flash boundary is the distance at which an unprotected worker would receive a second-degree burn from an arc flash incident energy of:
- 1.0 cal/cm²
- 1.2 cal/cm² (Correct answer)
- 2.0 cal/cm²
- 5.0 cal/cm²
Correct answer: 1.2 cal/cm²
The arc flash boundary is defined as the distance at which incident energy equals 1.2 cal/cm², the threshold for a just-curable second-degree burn.
Question 5: What does the term 'qualified person' mean in the context of electrical safety per OSHA standards?
- Anyone with an electrical license
- A person trained and knowledgeable in construction and operation of electrical equipment and hazards (Correct answer)
- A licensed master electrician only
- Any employee who has passed an electrical safety exam
Correct answer: A person trained and knowledgeable in construction and operation of electrical equipment and hazards
OSHA defines a 'qualified person' as one trained and knowledgeable about the construction and operation of equipment and the hazards involved.
Question 6: When must a lockout/tagout procedure be re-verified after it has already been established?
- Every 4 hours during the same shift
- When any worker leaves and returns to the job
- When the work scope changes or new hazardous energy sources may have been introduced (Correct answer)
- Lockout/tagout never needs re-verification once established
Correct answer: When the work scope changes or new hazardous energy sources may have been introduced
Lockout/tagout must be re-verified whenever the scope of work changes or new energy sources may have been introduced to the isolation.
Question 7: Which condition allows an electrician to use an energized electrical work permit under NFPA 70E?
- The task can be completed in under 15 minutes
- De-energizing creates a greater hazard or is infeasible due to equipment design or operational limitations (Correct answer)
- The worker has more than 5 years of experience
- The equipment is less than 240V
Correct answer: De-energizing creates a greater hazard or is infeasible due to equipment design or operational limitations
An energized electrical work permit is required when de-energizing creates a greater hazard or is infeasible due to equipment design or operational limitations.
IEC Electrical Safety Practices 2
When working on energized electrical equipment, which OSHA standard specifically governs electrical safety for general industry?