NEC ampacity tables, circuit sizing, and developing standardized tables

The basic design considerations and applicable codes and standards requirements necessary for proper circuit sizing are set forth, based on the 1990 National Electric Code (NEC). Consideration is given to load current, insulation temperature rating, equipment terminal requirements, ambient temperature, voltage drop, energy costs, equipment grounding conductor size, raceway effects, etc. Examples are given describing the typical but often incorrect method and several alternative, but correct methods. Finally, guidelines and examples are given on methods to streamline this process using computer-generated, standardized tables for feeders, motors, and transformers. These tables reduce design time and assure increased quality control in the design process