Common Residential PV System Code Violations
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The first residential PV projects were installed in locations far from the long arm of the building code establishment. As a consequence, many of the early PV installers were not familiar with or held to the standards set by the National Electrical Code, the International Building Code (IBC) and local jurisdictions. As the PV industry has grown, so has the need for strict compliance with these codes. Today’s PV installations often require multiple permits and inspections. Installation techniques and practices have evolved accordingly. In addition, many traditional ac electricians are entering the PV field and implementing electrical trade practices during installations.
The PV, building and electrical industries are constantly evolving as new equipment and methodologies are developed and released. Consequently, the governing codes are also constantly being updated to meet the requirements of their respective industries. This requires contractors to stay abreast of new information and requirements as they are released. Many new—and sometimes some old—issues about code compliance surface during PV system installation and inspection. To add to that difficulty, depending on the jurisdiction you work in, you may be held to current code cycles or sometimes to previous versions. This ultimately leads to confusion among contractors, PV installers, and enforcement and inspection officials, especially as these groups communicate with peers in other states and jurisdictions.
GENERAL CODE VIOLATIONS
The NEC is the guiding document for the electrical portion of PV installations. Some jurisdictions have specialty code requirements, but most are based on the NEC. While the NEC is considered the premier document guiding electrical installations, its acceptance and interpretation is determined by the AHJ, as outlined in Article 90.4.
Sloppy workmanship. One of the first requirements in the NEC appears in Article 110.12, which states, “Electrical equipment shall be installed in a neat and workmanlike manner.” While the Code does not and inspectors cannot define neat and workmanlike, they will know it when they see it. When work is neither neat nor workmanlike, it is a cue to inspectors to look even harder for additional Code violations. A National Electrical Installation Standard—Standard for Good Workmanship in Electrical Contracting published by the National Electrical Contractors Association—defines this requirement. (See Resources.)
Wire management is one critical issue to consider during installation. Since most PV modules come with factory installed quick connect plugs, it is not easy to use conduit to protect and manage the array wiring. The installer must properly support the wiring to prevent it from being damaged, especially where it could be exposed to physical harm. Jim Dunlop of Jim Dunlop Solar, and author of Photovoltaic Systems says, “One of the areas that I think can use some improvement is in the management of the PV source circuit conductors.” Most installers protect wiring from damage caused by roofing and racking. While rodents are not a widespread problem, some installers in the northeastern US also install guards along the array edges to discourage varmints from chewing on the wires and causing failures.
Not installed to listing. Another general NEC requirement is found in Article 110.3(B), which reads: “Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.” This covers a large number of considerations, from mechanical to electrical.
A common electrical mistake is to install an overcurrent protection device (OCPD), such as a circuit breaker or fuse, in a manner that violates the ampere rating specified by the inverter manufacturer. This can result in the conductors being inadequately protected or in nuisance tripping, which ultimately reduces energy production. While this problem may have been more prevalent in the early days of grid-direct installations, it still comes up today.
Improperly sized fuses or circuit breakers for PV source circuits present another issue. All PV modules come with a series fuse rating that should be used to determine the overcurrent protection size for the PV source circuits. It may be possible to use smaller fuses, but this generally does not benefit the installer. The bottom line is that the OCPD used to protect PV power circuits needs to be sized based on NEC Article 690.8, not based on what is on the truck that day.