Safe physical installation of photovoltaic solar panels
Electricians and builders should be aware that photovoltaic (PV) solar panels must be installed in accordance with the Australian Standards for buildings and the Building Code of Australia.
Incorrectly installed, PV solar panels can place stress on electrical wiring or be at risk of becoming dislodged, leading to serious safety risks.
Before installation, the correct location on the building should be chosen to site the panels based on manufacturer’s instructions, the wind load, the environment surrounding the building and the structure of the building.
The correct choice of brackets and method of attaching the bracket to the solar panel and the roof may vary depending on wind conditions and whether the building is constructed from timber or steel. AS 4100 should be referred to for steel structures and AS 1720.1 for timber structures.
It may be necessary to consult a structural engineer to ensure the installation of the panels will not lead to safety risks.
Issues to consider before installation:
Wind load – wind loads on roofs are directly related to building width, length, height and roof pitch. Refer to the standard AS/NZS 1170.2 Structural design actions part 2: Wind actions, AS 4055 Wind load for houses.
Wind Region – wind speeds vary across the country and have been separated into four wind speed regions. Information on wind speeds can be obtained from the Bureau of Meteorology. If the solar panels are to be installed in a high wind area, refer to Part 3.10.1 Volume Two of the Building Code of Australia, and consult with the relevant local councils for any local regulations.
Terrain Category and Topography – the surrounding terrain and its shape can have an effect on the wind loading of a house e.g. an exposed house will have significantly different wind effects to a house protected by other structures or vegetation.
Localised wind pressure – if a panel is mounted close to the edge of a roof, there will be more wind pressure on that panel than on a panel mounted in the centre of a roof.
Timber structures – consider the timber that the solar panel bracket will be mounted to - hardwoods versus softwoods; the rafter width; the screw joint direction into the rafter (side or top entry); the screw material, shank diameter and length; and the number of screws to ensure adequate fixing.