PV System Labeling

NEC, OSHA and ANSI Codes and Standards

Selecting appropriately matched components, determining correct wire sizes and overcurrent protection, and correctly installing all the equipment are critical elements of PV system design and installation that must pass inspection before the system can be turned over to the customer. The installer and inspectors are responsible for ensuring that a system meets the necessary codes and standards. One area that is most often overlooked and misunderstood is compliant labeling, which is required for any new system or any existing system that is being upgraded.

Either as a conscious decision or through a failure to understand current codes and standards, some installers omit necessary labeling. Some code officials are not aware of the labeling standards that they need to enforce for PV systems, so inadequate labeling goes unnoticed. Many jurisdictions have their own set of standards that they enforce, but these may be contrary to OSHA standards. It is no wonder that the PV industry as a whole is confused about what needs to be labeled and how.

The Origins of PV System Labeling

It is unknown exactly when the labeling of PV systems started, but what is important is that someone realized the value in doing so. There were few, if any, labeling requirements in the mid-1970s and early-1980s, when renewable energy systems started making their way onto the rooftops of residences across America. At that time, there were no easy methods to design and manufacture labels other than through a local trophy shop. Engraved labels became the norm for the industry.

The 1984 edition of the National Electrical Code was the first version of the Code to address solar electric systems. Labeling became part of the Code and, through subsequent revisions, grew to become an integral part of Article 690. Even though the NEC has gone through multiple editions since 1984, the common use of engraved labels has not changed.

Many installers and code officials recognize only engraved plastics, which typically employ white characters on a red plastic background, as the standard to follow. However, the designs and materials needed to comply with new regulations have changed. “Common Residential PV System Code Violations” (Dec/Jan, 2010, SolarPro magazine) lists labeling as one of the main areas of concern.

Labeling Functions

Labels protect workers and the general public by informing them about the hazards and characteristics of a PV system. Safety is paramount, and it is the most important aspect of labeling. A worker can become complacent and make a simple mistake that can cause a life-changing event. Labels provide the last line of defense in protecting a worker by offering a reminder at the hazard. PV systems have unique characteristics that must be accounted for. Labeling is a simple but effective tool to identify a hazard at the point of origin.

Labels provide critical information about operational parameters or about special operating characteristics. They identify components and subcomponents. A label is an essential communication tool that speaks both textually and graphically. Graphics are an essential element of effective labeling because they cross multicultural and educational boundaries. Pictograms are recognizable where words may not be understood. Label formatting—with vivid colors, safety alert or attention symbols, and bolded signal words— make safety labels easily recognizable.

Labeling Requirements

Most PV installers are familiar with the labeling requirements of NEC Article 690, but many installers, designers and owner/operators are not familiar with the requirements of OSHA Standard 1910.145, “Specifications for Accident Prevention Signs and Tags,” and it is often overlooked. The American National Standards Institute (ANSI) Z535 Series improved on the OSHA standard by changing old designs to modern ones that more accurately reflect potential hazards, suggest actions to avoid these hazards and give consequences for ignoring the intended message.

All labeling is mandatory and is meant to warn of electrical hazards associated with PV system installation and operation. NEC sections that mention labeling or marking require information that identifies system operational characteristics, directs personnel to component locations essential to worker protection and acts as a reminder to the nuances associated with photovoltaic systems. OSHA Standard 1910.145 applies just as other OSHA standards do and is as important as standards required for electrical work or for using fall protection when installing a PV system.

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