Which article covers systems that are not legally required but can be used for standby power?

Article 702 of the National Electrical Code (NEC) specifically addresses optional standby systems. These systems are designed for use when the primary power source fails, providing a reliable backup through generators or other sources. Unlike systems governed by codes requiring their use during emergencies, Article 702 focuses on installations that are not mandated by law but provide an additional layer of reliability for power supply.

This article outlines the requirements and guidelines necessary to ensure safety and functionality in such systems, including installation practices and proper connections to electrical loads. It also specifies provisions for transfer switches, maintenance, and adherence to local codes, ensuring that the optional standby systems can function effectively when needed.

In contrast, other articles mentioned—like Article 705, which deals with interconnections between different power sources; Article 708, which covers critical operation areas; and Article 760, which pertains to fire alarm systems—do not specifically focus on the concept of optional standby power sources, thereby solidifying Article 702 as the correct choice for this question.