In which scenario is a ladder not required to enter a manhole?

A ladder is not required to enter a manhole that is less than 4 feet deep because regulations often state that the use of a ladder is necessary primarily for deeper excavations to ensure safety and prevent falls. In scenarios where the depth is minimal, such as under 4 feet, it is generally considered low enough that a worker can safely conduct their tasks without the risk of falling. Safety standards aim to minimize hazards, and since the likelihood of a fall is significantly reduced in shallow spaces, the requirement for ladder use may be waived.

In contrast, using a safety harness does not negate the requirement for a ladder if the depth exceeds regulations for safe entry, while closing the manhole eliminates the need for entry altogether. Working at night does not influence the requirement for a ladder, as safety standards remain consistent regardless of time of day. Therefore, the condition of the manhole's depth plays a crucial role in determining if a ladder is necessary.