Which describes why rewireable fuses are less favored?

• A. They are rarely used
• B. People can tamper with them and insert inappropriate items like nails or foil
• C. They always trip on overloads
• D. They are more expensive than MCBs

Answer: (B)

Rewireable fuses are risky because the protective element is just a length of conductor that can be easily altered. The fuse relies on the wire melting at the correct current, but because the fuse can be opened, replaced, or adjusted by someone, it’s possible to tamper with it. People can insert inappropriate items—like nails or foil—or substitute a conductor with the wrong gauge, which can bypass the intended protection or prevent the fuse from operating properly. When protection can be defeated or circumvented, overcurrents may continue unchecked, creating serious fire and shock hazards.

Modern protective devices, such as MCBs or sealed cartridge fuses, provide more reliable, tamper-resistant protection with explicit current ratings and predictable disconnection behavior, which is why they’re preferred in contemporary installations. The other statements don’t capture this fundamental safety concern: rewireable fuses aren’t inherently rarely used, they don’t always trip in every overload scenario, and they’re not generally more expensive than MCBs in a way that would justify their use.