What could be a cause for a fuse and its holder in the panel to become hot?

The reason why a fuse and its holder in the panel can become hot relates to the physical connections and the overall condition of the electrical components. When another fuse is over-tightened, it can cause the bus bar to bend. The bus bar is the conductive metal strip that distributes electrical current to the various fuses in the panel. If the bus bar bends, it may not make a solid connection with the affected fuse, which can lead to increased resistance. Increased resistance generates heat due to the flow of electrical current, leading to the heating of both the fuse and its holder.

Moreover, when a fuse is not properly seated because of a misaligned bus bar, the electrical flow is compromised, resulting in further heat generation. This scenario emphasizes the necessity of careful installation practices and the importance of ensuring that all components are appropriately secured to prevent such heating issues.

While the first choice suggests that the fuse being the wrong size could cause overheating, the direct link to hot connections typically aligns more closely with mechanical issues like over-tightening and misalignment, particularly related to nearby components. This aspect makes the situation described in the correct choice more pertinent to the problem at hand.