Branch-Circuit Feeder and Service Calculations, Part XXIV

摘要

Requirements for calculating branch-circuit, feeder and service loads are in Article 220 of the National Electrical Code (NEC). Article 220 is divided into five parts. General requirements for load-calculation procedures are in Part I. Part II covers requirements for branch-circuit load calculations. Part III contains specifications for feeder and service load calculations. This part sometimes is referred to as the standard method for feeder and service load calculations. Part IV, "Optional Feeder and Service Load Calculations," contains optional load-calculation procedures for a single dwelling unit, an existing dwelling unit, a multifamily dwelling, two dwelling units, a school, an existing installation and a new restaurant. Part V provides calculation specifications for farm loads. Figure 220.1 (in the NEC) shows information on the organization of Article 220. Results from load calculations in Article 220, along with provisions from other articles, can be used to find conductor sizes and ampere ratings for overcurrent protection.