Line terminals, typically located at the top of the enclosure, receive incoming service from the utility. These are usually connected to thick black or red wires, each carrying 120V in a split-phase system. That cable running from your main service entrance to your distribution box isn't just another wire – it's the critical link that determines how safely and efficiently power flows through your entire building. Covers wiring, placement, standards, and expert tips for a compliant setup. A feeder usually begins with a feeder breaker at the distribution substation. It receives power from the main electrical supply and divides it into separate circuits, each.