An electrolyte is something can separates into ions and inherently has an ability to carry a charge. Therefore, since water does not dissociate appreciably into ions (although very rarely it can), it is not an electrolyte. Glass and sugar do not conduct electricity well, as they do not dissociate into ions. Sodium chloride is an ionic solid, meaning it is formed from the ions Na+ and Cl-, which can carry and transfer a charge, meaning sodium chloride is an electrolyte.