There are five electrical properties that have to be introduced in circuit theory to help with the analysis. These are resistance, capacitance, inductance, reactance, and impedance.
By strict definition a material can be classified as either a conductor, an insulator, or a semiconductor based on its electrical properties. Before getting into the definition of each of these, a brief introduction to atomic theory is in order.
Rule 10-812 specifies minimum grounding conductor sizes for low-voltage electrical systems up to 750 volts.