Article 706 Energy Storage Systems.
Code Change Summary: A new article was added to address energy storage systems.
The idea behind energy storage is to store energy for future use. There are many types of power production sources such as PV, hydro and wind systems that are used to generate energy but other systems such as storage batteries, capacitors, and kinetic energy devices (e.g., flywheels and compressed air) are all types of energy storage systems. The new article on energy storage resulted from the work of a large task group consisting of 79 people familiar with this technology.
The new article was derived by consolidating applicable resources from UL, NEMA and IEEE and placing them all into Article 706. At the beginning of the new article is an informational note which refers to 12 different standards commonly used when dealing with energy storage systems.
The new article contains rules including but not limited to the following:
706.4 System classification.
706.7 Disconnecting means.
706.8 Connection to other energy sources.
706.10 Energy storage system locations, ventilation, egress and guarding of live parts.
706.20 Circuit sizing and current.
706.21 Overcurrent protection.
Part III. Electrochemical energy storage systems.
Part IV. Flow battery energy storage systems.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC® edition of NFPA 70.
2017 Code Language:
706.1 Scope. This article applies to all permanently installed energy storage systems (ESS) operating at over 50 volts ac or 60 volts dc that may be stand-alone or interactive with other electric power production sources.
706.2 Definitions.
Energy Storage System (ESS). One or more components assembled together capable of storing energy for use at a future time. ESS(s) can include but is not limited to batteries, capacitors, and kinetic energy devices (e.g., flywheels and compressed air). These systems can have ac or dc output for utilization and can include inverters and converters to change stored energy into electrical energy.
Energy Storage System, Self-Contained. Energy storage systems where the components such as cells, batteries, or modules and any necessary controls, ventilation, illumination, fire suppression, or alarm systems are assembled, installed, and packaged into a singular energy storage container or unit.
Energy Storage System, Pre-Engineered of Matched Components. Energy storage systems that are not self-contained systems but instead are pre-engineered and field-assembled using separate components supplied as a system by a singular entity that are matched and intended to be assembled as an energy storage system at the system installation site.
706.10(D) Egress. A personnel door(s) intended for entrance to and egress from rooms designated as ESS rooms shall open in the direction of egress and shall be equipped with listed panic hardware.