How does a fused disconnect differ from a non-fused disconnect?

• A. It is rated for higher voltage only.
• B. Fused disconnects interrupt current under load; non-fused do not.
• C. Non-fused disconnects provide current interruption via mechanical means; fused do not.
• D. Fused disconnects provide current interruption via fuses; non-fused disconnect only provides isolation.

Answer: (D)

The main idea is how the current is stopped. A fused disconnect includes a fuse element in the circuit path, and when an overcurrent or fault occurs, the fuse melts and opens the circuit. This both isolates the section and automatically interrupts the current to clear faults and protect downstream equipment. A non-fused disconnect, by contrast, is just a switch used to isolate the circuit; it does not contain a fuse to interrupt current. It can provide a visible break for safe isolation, but it does not clear faults by itself—the current must be interrupted by upstream protection. So the fused type interrupts current via the fuse, while the non-fused type provides isolation only.