AS THE 2014 EDITION OF the National Electrical Code® approaches mid-cycle, nine new articles have been proposed for the 2017 edition of the NEC®, with four resulting in first revisions. Of those, three focus on the generation, distribution, and storage of electrical power, areas of considerable interest and activity in the electrical industry.
Proposed Article 691, Large-Scale Photovoltaic (PV) Electric Supply Stations, covers PV supply stations with a generating capacity of 5,000 kilowatts or more. The systems covered by this article differ from those covered in existing NEC Article 690, in that the power generated by a large-scale PV electric supply station is solely for the purpose of supplying power to an electric utility transmission or distribution system at medium or transmission-level voltages. Such facilities already exist and more are planned. Article 690 is oriented to utility-interactive or stand-alone systems that are used to directly supply a premises wiring system and is not a good fit for PV-generating facilities of this magnitude.
Proposed Article 706, Energy Storage Systems, provides requirements covering permanently installed systems that can be stand-alone or interactive with other electric power production sources. Historically, lead-acid batteries—and, more recently, new battery technologies used for energy storage—have been covered in Article 480. However, batteries are not the only form of energy storage devices available today. Flow batteries, capacitors, flywheels, and compressed air are other forms. The proposed article centralizes the requirements for all energy storage technologies, including the current requirements in Article 480, into a single NEC article.
Proposed Article 712, DC Microgrids, covers direct-current power systems where DC sources such as photovoltaic, wind turbines, and fuel cells supply power directly into a distribution system to supply DC utilization equipment such as LED lighting, communications equipment, computers and servers, variable speed motors, heating/ventilating/air conditioning equipment, and more. Efficiency is gained as the typical DC–AC, and then AC–DC, conversions are eliminated. DC distribution systems of this nature are currently being used in data centers throughout the world, and could in fact be used in any setting where on-site DC generation supply, such as a PV system, is used to supply a distribution system. Coupled with energy storage capability, such systems also provide for a reliable on-site system that is uncoupled from the typical offsite power system and thus not subject to interruptions occurring in the offsite sources.
The fourth first revision, Article 425, Fixed Resistance and Electrode Industrial Heating Process Equipment, covers equipment such as boilers, electrode boilers, immersion heaters, process air heaters, and other equipment that is used in a variety of industrial processes. The proponent of this revision cites a need for installers, designers, and authorities having jurisdiction to have a set of requirements for the safe installation of such equipment, which can have operating voltages ranging from 480 V up to medium voltage class (13.8 kV).
The other five recommendations for new NEC articles did not achieve first revision status, but are open for public comment (as are the four first revisions) that could result in their inclusion in the 2017 NEC.
More than 4,000 public inputs were processed for the 2017 edition of the code, from which 1,235 first revisions or changes were developed. The first draft report is scheduled for public access in mid July, and comments on the first revisions can be submitted online until September 25; paper submittals are due August 21. The revision process for the code will culminate with the issuance of the 2017 NEC in August 2016.