Which conducting electricity has the most harmful effects?

A conductor is an object or type of material that allows the flow of an electrical current in one or more directions. There are different types of conductors. Metals are traditional conducting materials. Examples are  copper (Cu), silver (Ag), and gold (Au).Example for Non metal conductor is carbon. 

The most harmful effect has every conductor with a flow of electrical current, because it can cause injury, nerve damage, cardiac arrest and death.