Which layout uses two separate feeders to supply electricity to critical customers?

• A. Radial layout
• B. Loop layout
• C. Ring layout
• D. Duplicate supply layout

Answer: (D)

Two independent power paths are used to keep critical loads powered even if one path fails. This approach, often called a duplicate supply arrangement, provides redundancy by feeding the same critical customers from two separate feeders, usually coming from different substations or routes. If one feeder trips or has a fault, the other can continue delivering electricity, keeping essential services online.

Radial layout relies on a single feeder from a substation, so a fault typically cuts power to all downstream customers. A loop (ring) layout ties feeders so power can flow around a fault, improving reliability, but it doesn’t inherently guarantee two completely separate feeders supplying the same critical customers. The duplicate supply layout explicitly uses two separate feeders to ensure continuous service for those critical loads.