The installation of a solar photovoltaic (PV) system is an increasingly attractive way to reduce the cost and environmental impact of producing and using electrical energy. However, these systems can also have an impact on safety for building occupants, electrical workers, and emergency responders. As more homes and businesses are fitted with PV systems, it is important to understand that multiple codes and standards across different disciplines must be applied to ensure a safe installation for all. Whether you are a system installer, property owner, or electrical inspector, finding all of the applicable requirements can be a bit like looking for buried treasure. In this blog post, I'll save you some digging and give you a map!
Reference #1 - NFPA 70®, National Electrical Code® (NEC®), 2020 edition establishes requirements for the safe use of electricity and electrical equipment by reducing or eliminating hazards, such as electric shock and fire. The following articles address PV systems as noted and either apply or modify the requirements found in the first four chapters of the Code:
Article 690 addresses PV systems other than the PV generating plant (solar farms) covered in Article 691.
Article 691 addresses large-scale systems with an inverter generating capacity of 5000 kW and greater.
Article 705 addresses installation of one or more electric power production sources operating in parallel with a primary source(s) of electricity.
Most jurisdictions adopt the NEC into law, as there are few alternative codes for electrical installation.
Reference #2 - NFPA 1, Fire Code, 2018 edition prescribes minimum requirements necessary to establish a reasonable level of safety and protection from fire, explosion, and dangerous conditions. Part of this code's objective is to ensure that firefighters can respond effectively and safely to a fire. PV systems are a concern for firefighters because, during a fire, roof-mounted PV systems can impede access to the roof or become a potential shock hazard. Where PV systems are installed on the ground, vegetation and near-by structures could provide a means of spreading fire, and the PV panels could become a shock hazard for anyone with access to the array(s). The following sections address these concerns:
Section 11.12.2 addresses roof-mounted systems and establishes requirements for marking and roof access.
Section 11.12.3 addresses ground-mounted systems and establishes requirements for clear space, vegetation management, and security.
Where the International Fire Code® (IFC®) is adopted instead of NFPA 1, similar requirements can be found in Section 1204 of the 2018 edition.
Reference #3 - NFPA 5000, Building Construction and Safety Code, 2018 edition provides minimum regulations for the safety of buildings and structures. The following section ensures that roof-mounted PV systems are securely supported by the building and mounting equipment:
Section 38.12 addresses roof-mounted systems and establishes requirements for mounting and support, wind design, and seismic design.
Where the International Building Code® (IBC®) is adopted, similar requirements can be found in Section 3111 of the 2018 edition.
Where the International Residential Code® (IRC®) is adopted, similar requirements for one- and two-family dwellings can be found in Section 324 of the 2018 edition.
Reference #4 - NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, 2019 edition outlines inspection and maintenance programs for industrial-type electrical systems and equipment. In order to reduce hazards due to failure or malfunction of the PV equipment, the recommendations of the following chapter should be followed:
Chapter 33 addresses maintenance of PV systems.
Similar recommendations can be found in CSA Z463-18, Guideline on maintenance of electrical systems.
Additional References - PV systems are sometimes supplemented with a means to store the surplus energy produced during the day so that it can be used at night. Where a battery or energy storage system is installed, the following references apply to that portion of the system:
NEC®, 2020 edition:
Article 480 addresses battery storage systems
Article 706 addresses energy storage systems >1kWh
Chapter 52 of NFPA 1, 2018 edition or Section 1206 of the 2018 IFC®
Where the IRC® is adopted for one- and two-family dwellings, Section 327 of the IRC®
In addition to these references, a new standard, NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, is currently being developed to address the hazards associated with energy storage systems.
Note that the references I've mentioned in the paragraphs above are applicable to privately-owned systems and might not apply to systems that are under utility control. Before proceeding with any design or installation, it is prudent to verify which editions of these codes have been adopted in your jurisdiction and to check whether any local amendments have been incorporated as well. The NFPA CodeFinder tool can help you get started.
On a final note, the documents I've identified can contain additional references that are either mandatory or simply helpful. I have chosen not to include those secondary references here. Use the comments section below to tell us about any references you think are particularly important or helpful for designing, installing, or maintaining PV systems.
We look forward to hearing from you. Thanks for reading!
NOTE: NFPA 70, National Electrical Code, and NEC are registered trademarks of the National Fire Protection Association.
International Fire Code, IFC, International Building Code, IBC, International Residential Code, and IRC are registered trademarks of International Code Council, Inc.