What is the difference between load and line wires?
Load wires collectively carry the power to the load. These wires can be driven from different sources, either through a connection to another circuit feeding into our branch box (assuming we have a load feed), or by connecting strings of lights together independent of other circuits (running parallel). In this latter case, loads “share” electricity from common incoming and outgoing lines, but the whole string will likely darken if any one wire fails between fixtures in that particular string. Line wire usually carries power directly to an end fixture. Both wiring methods are used and depend on designer’s preference according to application needs and space constraints as well as allowable currents per conductor in various residential electrical codes.