What is the problem and what is the reason for this fault?

When current is flowing via an earthing wire, also known as a grounding wire, this indicates that the hot wire, also known as the live wire, or something linked to the phase wire is making contact with the casing. For reasons of safety, the casing is connected to earth and ground by means of an earthing and grounding wire. This ensures that the current will flow out of the casing and not through a person, which might potentially cause them harm or even death. When there is electricity flowing through an earthing or grounding wire, there is a technical fault that poses a significant risk. Remove the plug and either have it repaired or dispose of it.