This electrical plan legend is a chart that contains all of the symbols used in a single diagram. It could be a mechanical, P&ID, or electrical symbol legend, among other things. This is a useful tool because it is impossible to remember every symbol in our diagrams. In an industrial setting, hundreds, if not thousands, of components can be used. A legend chart assigns a standardized symbol to each of those components and labels that symbol. Almost everyone has had to consult their car's owner's manual to determine what the various warning lights and gauges mean. Go ahead and start using EdrawMax to create house plans for your home.