Electrical power is the lifeblood of a modern building. It provides light, heating, cooling, and power for many electrical devices. Although there is great value in electrical power, it has shortcomings. If it is not handled properly, it represents a significant direct health hazard in the form of electrocution. Additionally, improper installation of wiring or electrical equipment has been the source of countless fires. For these reasons, several organizations have set up guidelines and regulations regarding the installation and use of electrical equipment. One of the most significant set of regulations is the NEC, or National Electric Code. This set of guidelines was first developed by the National Fire Protection Association (NFPA) in 1897, and has been updated every three years since then. Code-enforcement agencies may choose to enforce the current NEC codes, older editions of it, or alternate versions that incorporate local modifications. Designers and electricians should verify the codes and editions in force and consult authorities having jurisdiction (AHJ) regarding their interpretations of ambiguous or conflicting requirements. This module describes how power is delivered to and distributed throughout a building. It also covers some of the major code issues governing this process.
