This chapter covers electrical installations involving special conditions and systems that require requirements beyond the general rules of the NEC. Chapter 7 includes topics such as emergency systems, legally required standby systems, optional standby systems, critical operations power systems, interconnected electric power production sources, energy storage systems, and other specialized electrical systems.Use this page to study the Code section by section, understand when these special requirements apply, and connect the rules to real-world electrical installations. Whether you’re an apprentice building your NEC knowledge or an experienced electrician reviewing specialized systems, this is your place to work through Chapter 7.