Insulative materials do not allow charges to move across their surfaces or through their volume. Charge placed in one spot on an insulative object will stay in that location. If a charged insulator is grounded, charges will not move to ground. Grounding is not an effective method of neutralizing insulators.

Insulators can have both negatively and positively charged areas on the same object. Because insulators do not allow charge movement, they can accumulate massive amounts of charge. Static fields on insulators are not necessarily permanent; they will eventually be neutralized by gradual recombination with free ions.