Installation of Photovoltaic Systems - Code Compliance Brief

The intent of this brief is to provide code-related information about photovoltaic systems to help ensure that what is proposed regarding the photovoltaic ‘product’ itself, including accessories such as inverters and controls, as well as their individual and collective installation can be verified as being in compliance with safety-related codes and standards for residential construction.  Providing consistent information to document compliance with codes and standards to all relevant parties responsible for verifying compliance with those codes and standards (e.g., code officials, builders, contractors, designers, utilities, fire officials, etc.) is expected to result in increased compliance and more timely, less challenging and more uniform plan review and field inspections.

Photovoltaic systems can provide power for a single use or building, be connected to the utility grid, or could be a hybrid of the two.  They can be mounted on building roofs or walls, integrated as an actual component of roof or wall construction, or simply mounted at grade or elevated above grade on a supporting framework. Codes that are relevant to such systems when installed on, as part of, or adjacent to a home include the National Electric Code (NEC), the structural sections of the International Residential Code (IRC), and the renewable-energy sections of the International Energy Conservation Code (IECC) as well as a number of safety standards that area referenced in these documents and address portions of the photovoltaic system (e.g. IEEE or Underwriters Laboratory [UL standards] as referenced in these documents and applicable to the photovoltaic system and its components). Source: Institute of Electronics and Electrical Engineers, Standards Association, https://standards.ieee.org/ . The installation of photovoltaic panels on a building roof or integral with a building roof also  raises other code issues (e.g., roof loading, wind loading, fire ratings, weather tightness, mounting systems, roof penetrations, etc.), which may also be relevant for systems mounted on or integral to a wall.

An increased number of photovoltaic systems are being deployed to help meet household energy needs.  For a home to qualify as a U.S. Department of Energy Zero Energy Ready Home (DOE Solar Energy Ready Program Requirements, http://www.energy.gov/sites/prod/files/2014/04/f15/doe_zero_energy_ready_home_requirements_rev04.pdf), it must be constructed, at a minimum, as “solar energy ready.” Any initiative focused on the application and use of wind, photovoltaic, or other renewable resources will likely require the installation of a system to store excess energy for subsequent use (refer to the referenced Code Brief on Design and Installation of Electrical Energy Storage Systems for additional information and the Database of State Incentives for Renewables and Efficiency at http://www.dsireusa.org/.  Beyond this DOE initiative, some builders and homeowners choose to install photovoltaic systems—whether they are participating in a program or not—simply to have power from non-utility sources to reduce their monthly electric bills as well as to enhance the value and appeal of the home. This brief provides further clarification and resources to assist with designing, constructing, and installing these type of systems and/or system components and verifying that they are safe and meet code. The intent of solar energy ready requirements is to provide a penetration free and shade free portion of the roof, called the solar zone. This helps ensure future installation of a solar energy system is not precluded by the original design and layout of the building and its associated equipment.

The following sections list the applicable code and standard requirements and details helpful for Plan Review.  The Field Inspection section then provides details for inspecting “… photovoltaic systems.”  For resources on technical validation, best practices, and measure guidelines, refer to the Technical Validation/Reference Materials section of this brief.

The lists and provisions provided below in each section are intended to target the primary code sections and provisions.  There may be other references, code sections, standards, testing methods, etc., that affect the technology or other assemblies or functions of the building.