Solar power is one of the fastest-growing green energy sectors. It is clean, renewable and cost-efficient, but there are many hazards associated with the manufacturing, installation and maintenance of solar energy equipment. There have been numerous injuries and fatalities doing this type of work, so it is important to understand how to identify and mitigate these hazards.

Solar power is created when solar photovoltaic (PV) panels turn the sun’s rays (or photons) into electricity (or voltage). This is known as the photovoltaic effect.

According to the nonprofit RE-volv’s “Solar Energy 101” webpage, “The basic unit of a solar panel is a solar cell, made out of silicon wafers similar to those used in computer chips. These cells are combined in solar modules, which are combined into solar panels, which produce electricity. Your solar electricity is then sent to an inverter, which transforms the electricity from DC (direct current) to the AC (alternating current) that we use in our homes and appliances. The inverter then feeds this AC electricity to the building’s electrical panel, allowing it to power the electrical appliances and lights in the building.”

What are the risks?

Individuals working in the solar power industry may encounter arc flash, electric shock, crane and hoist hazards, falls, heat and cold stress and thermal burns. Standards such as the National Electrical Code and the specific electric utility that the system will be connected to are two sources that provide minimum interconnection requirements. In addition, applicable electrical safety standards such as NFPA 70E, Standard for Electrical Safety in the Workplace, should be used. When connecting to a grid, the Occupational Safety and Health Administration Electric Power Generation, Transmission and Distribution Standard (29 CFR 1910.269) applies.

Solar electric systems have two electrical power sources: the utility and the solar power system. As a result, shutting off the main breaker will only turn off the utility power, and will not shut off the solar electric array. Electricians need to be aware of this when working on electrical systems using solar energy. Additionally, electric shock and arc flash precautions should be taken when working on these electric systems.

According to Oregon’s Solar Construction Manual, “Electricians are used to isolating the ‘load’ from the power source (usually with a breaker or other disconnect switch) and then they proceed to work on that ‘safed zero energy load.’ With a solar electric system, you work on the power source itself (the PV panels or associated wiring)—this is fundamentally different than working on a ‘safed load’ and you must keep this in mind. Even low light conditions can create a voltage potential that can lead to a shock or arc-flash. A surprise shock delivered at the wrong time could cause a fall from a roof or ladder.”

Some solar electric systems have a battery backup, which can pose the most dangerous hazards in solar electric maintenance and installation.

Oregon’s Solar Construction Manual notes, “Care should always be taken to prevent arcing at or near battery terminals. Always open the main DC disconnect switch between the batteries and the inverter prior to servicing or working on the battery bank. Battery banks can store voltages with very high current potential. These higher potentials can create electrical arc hazards.”

Safety requirements

Workers must observe the usual measures required for protection against arc flash and shock. Examples include removing all jewelry and wearing arc-rated clothing and other applicable PPE.

Lead, which can leak out of lead-acid batteries, can result in reproductive harm, and leaking acid can cause severe chemical burns. Even dead batteries can be dangerous and need to be properly disposed of.

Solar panels and electric systems are often very heavy and placed on top of or on the edge of roofs or at significant heights. As a result, cranes may be required for installation. Workers involved with this process should abide by all general industry requirements pertaining to cranes, hoisting and rigging. They also need to use the appropriate fall protection when working from elevated positions and try to mitigate the risk of any struck-by hazards.

For obvious reasons, the surface of a PV panel gets very hot; therefore, thermal burns are a major threat to individuals working on or near components. Employers must provide appropriate PPE to prevent burns and other possible hazards, which workers must wear and use properly.

Finally, because solar power systems are installed outdoors, it is important that workers are prepared for weather conditions, especially extreme heat or cold. This means dressing appropriately and limiting time in the elements.