In what situation should wrenches not be used?

Wrenches should not be used as a hammer because they are not designed for impact applications. Using a wrench this way can not only damage the wrench but also lead to injury or accidents due to the unexpected force applied to the wrench head, which may cause it to slip or break. This misuse can compromise the integrity of the tool and lead to failure in performing its intended function.

In contrast, the other options describe situations where a wrench might be more appropriately used or at least considered, despite potential limitations or specific requirements. For example, wrenches can be utilized for tasks like tightening five-sided nuts or removing difficult hex-headed bolts, albeit with certain precautions based on the size or condition of the fasteners. As a leveling device, it might not be ideal, but it does not inherently pose the same risks associated with using a wrench as a hammer. Therefore, the clear distinction lies in the fact that using a wrench as a hammer goes beyond its intended purpose and can lead to safety hazards.