AEP Code Compliance & Standards 3 — Questions and Answers
Question 1: When performing lockout/tagout under OSHA 29 CFR 1910.147, after isolation and lockout, what is the required next step before beginning work?
- Notify the control room operator
- Verify zero energy state by testing for absent voltage (Correct answer)
- Attach all required tags to the lockout device
- Complete the written energy control procedure
Correct answer: Verify zero energy state by testing for absent voltage
After lockout, the worker must verify the zero-energy state by attempting to start or test the equipment and confirming absence of voltage.
Question 2: According to NFPA 70E Table 130.5(C), which task is likely to require the highest incident energy PPE level?
- Reading a panel meter from outside an enclosure
- Operating a 480V circuit breaker with the door closed
- Racking in a medium-voltage circuit breaker with the door open (Correct answer)
- Replacing a fuse in a 120V lighting panel
Correct answer: Racking in a medium-voltage circuit breaker with the door open
Racking in medium-voltage circuit breakers with open doors exposes workers to the highest arc flash potential, requiring the highest PPE level.
Question 3: Under NEC Article 110.9, overcurrent protective devices must have an interrupting rating sufficient for the available:
- Full-load current at the point of installation
- Short-circuit current at the point of installation (Correct answer)
- Ground fault current at the service entrance only
- Overload current expected during motor starting
Correct answer: Short-circuit current at the point of installation
NEC 110.9 requires that devices have an interrupting rating equal to or greater than the available short-circuit current at the point of installation.
Question 4: Which IEEE standard defines the requirements for transformer protection and the settings for differential relays on large power transformers?
- IEEE C57.12.00
- IEEE C37.91 (Correct answer)
- IEEE C37.110
- IEEE C57.131
Correct answer: IEEE C37.91
IEEE C37.91 provides guide for protective relay applications to power transformers, including differential relay settings and considerations.
Question 5: In electrical safety, what does 'flash hazard analysis' determine according to NFPA 70E?
- The probability of a flashover occurring on overhead lines
- The incident energy level and required PPE for a specific work task (Correct answer)
- The arc flash distance required for non-electrical workers
- The minimum safe distance from energized equipment for all personnel
Correct answer: The incident energy level and required PPE for a specific work task
Flash hazard analysis calculates the incident energy at a work location to determine required PPE category and arc flash boundary.
Question 6: AEP's transmission operations must comply with NERC Reliability Standards. Which NERC standard addresses transmission planning and steady-state voltage requirements?
- FAC-001
- TPL-001 (Correct answer)
- MOD-026
- PRC-005
Correct answer: TPL-001
NERC TPL-001 establishes transmission planning standards, including steady-state performance requirements under various contingency levels.
Question 7: Under OSHA 29 CFR 1910.269, what is the minimum insulation rating required for rubber insulating gloves used by qualified electrical workers at 15kV?
- Class 0 (1,000V rated)
- Class 1 (7,500V rated)
- Class 2 (17,000V rated) (Correct answer)
- Class 3 (26,500V rated)
Correct answer: Class 2 (17,000V rated)
Class 2 rubber insulating gloves are rated to 17,000V and are the minimum required for work on 15kV class equipment.
AEP Code Compliance & Standards 3
When performing lockout/tagout under OSHA 29 CFR 1910.147, after isolation and lockout, what is the required next step before beginning work?