Safety alert for installers of PV systems

The Queensland Electrical Safety Office has issued a safety alert to highlight the risks associated with direct current (DC) isolators used in solar photovoltaic (PV) systems. The office has been made aware of a number of instances in Queensland where direct current (DC) isolators have failed due to poor circuit connections and where isolators have shown signs of being affected from the intrusion of moisture or have had signs of water damage present.

When terminating electrical conductors into isolators and circuit breakers, it is paramount that connections are secure under the terminal clamp especially where DC is involved. Shoddy practices can result in unsafe solar PV systems, particularly where equipment such as direct current isolator enclosures or junction boxes are not suitably installed to prevent water ingress.

In accordance with the PV standard AS/NZS 5033, all equipment exposed to the outdoor environment must be at least IP54 compliant in accordance with AS 60529 and be UV resistant. Higher IP ratings should be considered for tropical regions. Junction boxes and combiner boxes adjacent to the PV array and located in areas that may be affected by water jets associated with cleaning must be a minimum of IP55 compliant.

Any enclosure IP rating shall suit the environmental conditions and apply to the relevant mounting position. Unless otherwise stated by the manufacturer, the IP rating should be assumed to apply to a vertical mounting orientation. Any flaps on enclosures required to achieve the IP rating should latch automatically when released from the fully open position.

The practice of drilling holes in IP-rated equipment is not acceptable. Electrical contractors have an obligation to ensure all installations are electrically safe including that connections are not loose and verification that wiring systems are protected from external influences.

Electrical contractors must: install only DC isolators rated for the voltage and/or current output of the system; confirm polarised DC isolators are wired correctly and are rated for direct current; ensure the required documentation as outlined in the PV standard is provided to the PV system owner; ensure the way electrical equipment or installation is installed is electrically safe.

It is important to follow the correct installation processes recommended by each equipment manufacturer.