Maintenance, Repair & Operations

NEC Requirements for Energy Storage Systems

July 21, 2020

Key points of Art. 706

The requirements for energy storage systems were heavily changed with the 2020 National Electrical Code (NEC). That should come as no surprise, given the massive increase in large-scale wind and solar power generation systems. Article 706 provides the requirements for energy storage systems that have a capacity greater than 1kWh [706.1] and are capable of providing power to the premises wiring system or to a power distribution network [706.2].

Some key points include:

The disconnecting means must meet the requirements enumerated in 706.15(A)(1) through (3).
The disconnecting means must be installed per the requirements of Part III and 706.15(B) through (D).
Article 706 has its own requirements for conductor sizing [706.30], but you size overcurrent protection per Article 240 [706.31(A)].
Overcurrent protection devices for any dc portion must be listed for dc, and have the appropriate voltage, current, and interrupting rating for the application [706.31(C)].
The system must have provision for charge control. Adjustable means for control of the charging process must be accessible only to qualified personnel [706.33(A)].
A system using flow batteries must comply with Part V.

About the Author

Mark Lamendola

Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.

Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.

Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.