This standard provides a basis for Showing the general physical location and arrangement of the sections of the required wiring system Identifying the physical requirements for various types of materials needed to provide the electrical installation in buildings In some instances, the symbols may indicate the function or electrical characteristics of the system; however, that is not their primary purpose. Such functions or characteristics are shown by the use of the graphic symbols for electrical diagrams, as specified in American National Standard Y32.2-1970, Graphic Symbols for Electrical and Electronics Diagrams (IEEE Std 315-1971). The required installation is shown on the drawing by the use of the various applicable outlet and equipment symbols, together with interconnecting circuit or feeder run lines, supplemented with necessary notations. In general, basic symbols have been included in the symbol schedule. In some instances, the use of numbers or letters of the alphabet drawn in, or at the side of, the basic symbol to identify a specific application of the symbol for a particular type or use of outlet may be required. In some instances, the physical or electrical size of the item identified by the symbol will be noted to one side of it.