When should you never use a metal ladder?

Using a metal ladder near electrical sources is highly discouraged due to the significant risk of electric shock. Metal is a conductive material, meaning that if the ladder comes into contact with an electrical source, such as live wires or equipment, it can carry electricity and create a dangerous situation for anyone on or near the ladder. This presents an immediate danger that can result in severe injury or even death.

In contrast, the other options address different safety considerations that, while important, do not carry the same level of immediate peril associated with electrical hazards. For instance, windy conditions might affect ladder stability, and working indoors could be less hazardous but does not eliminate the risk present when dealing with electrical sources. Long work durations can lead to fatigue but do not pose an inherent hazard linked to the materials of the ladder itself. Understanding when and how to choose the proper ladder for specific environments can significantly enhance safety in everyday tasks.