For a 275 kV line, which of the following is a typical required clearance?

For a 275 kV line, which of the following is a typical required clearance?

• A. 10 feet
• B. 20 feet
• C. 30 feet
• D. 40 feet

Answer: (B)

Maintaining a safe air gap between energized lines and nearby equipment or personnel is essential to prevent electrical arcing and unexpected contact. The higher the voltage, the larger the gap needed to keep the air insulator effective and to accommodate any movement of lines or rigging. For a 275 kV line, about 20 feet is a typical minimum clearance used in practice. This distance accounts for normal variations such as line sag, wind-induced movement, and the reach or swing of rigging and equipment like cranes. It provides a practical, conservative buffer that helps ensure that even with equipment movement or weather effects, the arc threshold isn’t crossed. Smaller clearances (like 10 feet) would be unsafe for this voltage level, while larger clearances (30 or 40 feet) are more conservative than what is normally required in standard operations, unless unusual conditions or stricter safety policies apply.

Maintaining a safe air gap between energized lines and nearby equipment or personnel is essential to prevent electrical arcing and unexpected contact. The higher the voltage, the larger the gap needed to keep the air insulator effective and to accommodate any movement of lines or rigging.

For a 275 kV line, about 20 feet is a typical minimum clearance used in practice. This distance accounts for normal variations such as line sag, wind-induced movement, and the reach or swing of rigging and equipment like cranes. It provides a practical, conservative buffer that helps ensure that even with equipment movement or weather effects, the arc threshold isn’t crossed.

Smaller clearances (like 10 feet) would be unsafe for this voltage level, while larger clearances (30 or 40 feet) are more conservative than what is normally required in standard operations, unless unusual conditions or stricter safety policies apply.