Which factor can significantly affect the impact of an arc on an employee?

The distance from the arc is a crucial factor that significantly influences the impact of an arc on an employee. As the distance increases, the intensity of the heat and radiant energy produced by the arc diminishes, thereby reducing the likelihood of injury or burns. Close proximity to an arc can lead to severe injuries due to extreme temperatures and thermal radiation, which can cause skin burns and ignite clothing. Therefore, maintaining a safe distance from an arc source helps protect employees from these potential hazards.

In evaluating other factors, while equipment type, moisture presence, and ambient temperature can have their own impacts on safety and working conditions, they do not have as direct an effect on the immediate consequence of an arc as the distance does. Equipment may influence the method of protection or the type of protective gear required, moisture can increase electrical conductivity, and ambient temperature may affect the overall working environment, but the distance from an arc remains paramount to directly mitigating the immediate risks associated with arc flash incidents.