Incoming line part: Displays the incoming line source of the distribution box, which may be a single-line incoming line or multiple-line incoming lines (such as normal power supply and backup power supply), and marks the model and rated breaking current of the. Incoming line part: Displays the incoming line source of the distribution box, which may be a single-line incoming line or multiple-line incoming lines (such as normal power supply and backup power supply), and marks the model and rated breaking current of the. This standard describes requirements for numbering and labeling of real property electrical distribution equipment, circuits, and site lighting at Lawrence Livermore National Laboratory. This is an internal LLNL standard meant to guide the design of new facilities, facility modifications, and. Electrical power enters a distribution box through the incoming lines using what we call a five-wire system. Each of these wires has a specific, non-negotiable purpose: The Phase Lines : You've got three of these bad boys – A, B, and C phases. By convention, we use yellow for A phase, green for B. Here is a simple table that shows what it does: Sends electricity from the main supply to each circuit. Every area gets the power it needs. Uses breakers or fuses to stop too much current. Isolator Base should withstand the breaking capacity of 80 kA. To extinguish the arc immediately in iso ators, in each phase arc-chutes with minimum 12 strips ype. Why it's required? Whether you have a new or existing facility, the single-line diagram is the vital roadmap for all.