An electrical conductor is a substance in which electrical charge carriers, usually electrons, move easily from atom to atom with the application of voltage.Conductivity, in general, is the capacity to transmit something, such as electricity or heat.ases are normally poor conductors because the atoms are too far apart to allow a free exchange of electrons. However, if a sample of gas contains a significant number of ions, it can act as a fair conductor. A substance that does not conduct electricity is called an insulator or dielectric material.