Unnecessary insulators are all other insulators not necessary to perform the given work at the ESD safe work station. Some examples are styrofoam coffee cups, radios, notebooks, phones, plastic bins, etc. The electrons on the outer shell of an atom. An electrical charge at rest on the surface of an object. The discharge of electrons to earth.
Static charge is generated when lightning strikes.
Static charge is generated only in extremely dry environments. During humid conditions, such as a thunderstorm. In a hot, dry climate, such as a desert. In any environment, under any weather conditions. The sudden movement of a static charge from one object to another.