Solar America Board for Codes and Standards Releases Report on Electrical Grounding of Photovoltaic Systems

Las Cruces, NM – November 14, 2012 – The Solar America Board for Codes and Standards (Solar ABCs) has released a report, "Photovoltaic System Grounding," which addresses the requirements for electrical grounding of photovoltaic (PV) systems in the United States. As PV systems age, grounding issues emerge that impact system safety. These issues include deteriorating electrical connections and inadequate grounding device design and installation.

This report explains what grounding is and defines different types of grounding. It also describes existing National Electrical Code®(NEC®) grounding requirements, explains the basics of grounding PV equipment and systems, and notes the U.S. organizations responsible for developing and publishing grounding and safety standards. The NEC establishes the legal installation requirements for PV systems, and the requirements are somewhat complex. This report clarifies some of these complexities and suggests grounding configurations appropriate for PV systems. "The Solar ABCs commissioned this work to provide the PV industry with practical guidelines and procedures to ensure reliable PV system grounding," said Larry Sherwood, Solar ABCs Project Administrator, "as well as ensure the ongoing safety of these systems."

A number of organizations are involved in the process of determining reliable grounding protocols for PV systems. Although the NEC does not specifically mandate that all equipment be certified/listed, it does require electrical inspectors to examine all electrical equipment for safety. Many local jurisdictions only allow the use of equipment certified/listed through the U.S. Occupational Safety and Health Administration’s Nationally Recognized Testing Laboratory Program, because they feel unqualified to examine uncertified/unlisted equipment for safety, as the NEC requires. In addition, Underwriters Laboratories (UL) coordinates the development of many of the hardware safety standards that apply to PV systems. The NEC covers premises wiring up to the "service point," at which point the utility installation requirements, established by the National Electrical Safety Code (NESC) and other Institute of Electrical and Electronic Engineers (IEEE) standards, begin.

The PV industry must work closely with these organizations as they shape the standards affecting grounding in PV systems. This diligence will reduce uncertainties for electrical inspectors as well as PV system installers and owners, and ensure that PV systems are safe throughout their long lifetimes. Revisions of the NEC and UL safety standards for the certification/listing of equipment are underway, and will help to address many of these issues.
Download the full report:

About Solar ABCs
The Solar America Board for Codes and Standards (Solar ABCs) is a collaborative effort among experts to formally gather and prioritize input from the broad spectrum of solar photovoltaic stakeholders including policy makers, manufacturers, installers, and consumers resulting in coordinated recommendations to codes and standards making bodies for existing and new solar technologies. The U.S. Department of Energy funds Solar ABCs as part of its commitment to facilitate widespread adoption of safe, reliable, and cost-effective solar technologies.

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Media contact: Mr. Larry Sherwood, 303-413-8028