Q70 — Breaker Tagging / Removal from Energized Bus
G2.2.13 (4.1)
Given:
• Unit 2 is in MODE 5 during a scheduled maintenance outage.
• A Red Blocking Tag (RBT) is hung on a 460V breaker racking mechanism.
• The 460V Bus associated with the breaker is energized.
• The breaker is tagged in the "Disconnect" (DI) position.
Which ONE of the following describes the required tagging sequence when removing the breaker from its cubicle to facilitate maintenance?
[REFERENCE PROVIDED]
• Unit 2 is in MODE 5 during a scheduled maintenance outage.
• A Red Blocking Tag (RBT) is hung on a 460V breaker racking mechanism.
• The 460V Bus associated with the breaker is energized.
• The breaker is tagged in the "Disconnect" (DI) position.
Which ONE of the following describes the required tagging sequence when removing the breaker from its cubicle to facilitate maintenance?
[REFERENCE PROVIDED]
A. The RBT will be removed from the breaker but kept active and maintained in the physical possession of Operations while the breaker is out of the cubicle.
B. The RBT will remain on the breaker racking mechanism, the breaker removed from the cubicle and an additional RBT installed on the cubicle door.
C. The RBT will remain on the breaker racking mechanism, the breaker removed from the cubicle and a White Caution Tag installed on the cubicle door and red danger rope will be hung across the cubicle opening.
D. The RBT will be removed from the breaker racking mechanism, the breaker removed from the cubicle, a red danger rope, tape or FME device will be hung across the cubicle opening and the same RBT installed on the rope.
▶ Show Answer & Explanation
✓ D. Correct. IAW OP-AA-109-115, Safety Tagging Operations. (See Attachment 2, section 11.4, Breaker Tagging); "If the bus is energized, and the breaker is being removed, then a red danger rope, tape or FME device will be hung (inside the cabinet) across the opening with a warning sign posted stating the bus is energized. The tag is transferred to the red rope or tape."
✗ A. Incorrect. Plausible because the candidate may focus on the fact that maintenance cannot be conducted on a tagged component. They may think of the evolution as a temporary release of the tags. Incorrect as the associated bus is still energized and a safety boundary still needs to be established and controlled IAW OP-AA-109-115, Safety Tagging Operations. (See Attachment 2, section 11.4, Breaker Tagging)
✗ B. Incorrect. Plausible because the candidate believes the additional RBT on the cubicle door is an acceptable safety boundary IAW the safety tagging program. Incorrect as the breaker cannot be worked on or removed with a RBT still attached.
✗ C. Incorrect. Plausible because the candidate may believe that the addition of a White Caution Tag is an acceptable method of configuration control and that the safety boundary is met with the red danger rope across the cubicle opening. Incorrect, the RBT must be removed from the breaker and a RBT must be utilized and attached to the red danger rope.
Ref: OP-AA-109-115, Safety Tagging Operations | LO: N/A | Source: Bank, Vision Database | Cognitive: Fundamental
Connections
- Related systems: 460/230V AC
- Related procedures: OP-AA-109-115 — Equipment Tagging
- Related exam: 2020 NRC Written Exam