This post is short. It’s to the point. The title says it all . . . .
Schematic diagrams show details like the cable scheme number, which is the basis for numbering the cables associated with that particular system. Scheme numbers are often based on the breaker that feeds the system, but they may be based on the equipment tags also.
Schematic diagrams also have block diagrams that illustrate how many cables are routed between devices like panels, motors, and MCCs. The block diagrams show the names of cables and their conductors. The conductor names are generally used in the schematic diagram itself, and the cable names are shown on the block diagram. There are exceptions to this rule.
New equipment will need to fit within the existing schemes and comply with the plant’s numbering format, especially if new schemes need to be created. These types of details don’t need to be made final immediately, especially when first drafting your drawings. But they shouldn’t be overlooked, and they will remind you to start thinking about what labels you will give your equipment, cables, and conductors.