Death highlights dangers of extra-low-voltage solar PV

Queensland’s Electrical Safety Office (ESO) has investigated the electrocution of a person who was modifying the solar panels on an off-grid solar PV system in a remote area. The deceased was found with significant burns to their hands and fingers.

The ESO found that the solar PV system had been operating at around 100 VDC, which is classified as an extra-low voltage, ie, not exceeding 50 VAC or 120 V ripple-free DC. Given the extra-low voltage, the person performing the work was not required to be a licensed electrical worker; however, this incident sadly highlights the real risk of working on such installations.

The ESO cautioned that anyone working on solar PV systems requires specific skills and knowledge to understand electrical safety and installation requirements, particularly when it comes to DC voltages.

A licensed electrician must always be engaged to carry out work involving installation and maintenance of solar PV systems that are operating at and above low voltage (greater than 120 VDC and greater than 50 VAC).

Safe work practices and compliance to safety standards for equipment and installations is imperative, and can reduce risks associated with such systems, such as electric arcing, electric shock and fire risks.

The ESO urged workers to consider the following issues:

• Even at extra-low voltage there can be significant electrical current in solar PV systems that can cause arcs and burns to the body (even solar panels operating at extra-low voltage create electricity while the sun shines on the panels). Panel-to-panel connections and disconnections are a significant risk.
• Health issues could compromise situations, even at extra-low voltages, because cuts, wounds or ulcers can reduce resistance or medical issues involving pacemakers can be aggravated.
• Environmental conditions (such as high humidity or wet seasons and heavy rain) can increase risks, especially if the extra-low voltage is at the higher range.
• Remote locations may have difficult access, which could hamper assistance, so extra precautions are warranted.
• If located on a roof or other structure, there are working from heights and fall risks, as well as when accessing the roof (ensuring secured ladders).
• Failure to weatherproof the electrical parts creates a fire risk.
• Safety standards to ensure safe means of isolation should be followed.
   

The exact effect from extra-low voltages depends on the size of the voltage, which parts of the body are involved, how damp the person is and the length of time the current flows.

Regardless of voltages present, safety standards for equipment and installations should be followed to reduce risks associated with any solar PV systems.

It’s also important, the ESO said — especially in a remote area where there may be high humidity — that risk assessments and mitigating actions are taken to reduce the chance of shock, burns or fires while working on or using extra-low-voltage solar PV systems.

For more information, read the Managing electrical risks in the workplace code of practice 2021 document (PDF, 1.25 MB).

Image credit: iStock.com/jamesbowyer