Where are primary ducts located?

Where are primary ducts located?

• A. On the top
• B. On the bottom
• C. In the middle
• D. On the side

Answer: (B)

Primary ducts are located at the bottom of an underground duct bank. This arrangement places the most critical and high‑voltage feeders deepest, providing maximum protection from surface activity, potential damage from digging or equipment, and easier separation from other, less critical circuits placed above. Keeping the high‑priority conductors lower helps with safety and maintenance, since the upper layers can be organized to accommodate the remaining circuits without encroaching on the protected primary level. If the primary ducts were higher up, they’d be more exposed to damage and handling during construction and service work, which is why the bottom position is preferred.

Primary ducts are located at the bottom of an underground duct bank. This arrangement places the most critical and high‑voltage feeders deepest, providing maximum protection from surface activity, potential damage from digging or equipment, and easier separation from other, less critical circuits placed above. Keeping the high‑priority conductors lower helps with safety and maintenance, since the upper layers can be organized to accommodate the remaining circuits without encroaching on the protected primary level. If the primary ducts were higher up, they’d be more exposed to damage and handling during construction and service work, which is why the bottom position is preferred.