Survey shading and choose roof or ground mounting
Shade on even part of a panel can cut its output sharply, and the best mounting spot decides tilt, cable length and maintenance access. Choose the location before you size cables or buy racking.
How
- Walk the site at different times of day and, ideally, in winter when the sun is lowest. Note trees, buildings, hills and future growth to the equator side of the array.
- Compare roof and ground options. Roofs save land and are already high, but tilt and azimuth are fixed by the roof, and access for snow clearing and cleaning is harder. Ground mounts allow ideal tilt, easy cleaning and cooler panels, but need land, footings and longer cable runs.
- Decide before you buy: a ground mount feeding a separate power shed avoids some rooftop rules. Example (US NEC 690.12): PV circuits on or in a building need rapid shutdown, but ground-mount conductors entering a building that only houses PV equipment do not (power-18).
- Face the array towards the equator (south in the northern hemisphere, north in the southern) unless the tools show a better result. PVGIS can calculate optimal slope and azimuth for you.
- Keep the array as close as practical to the battery and inverter room to limit voltage drop (step power-17).
- Check with the design module that the roof structure can carry panels, racking, wind uplift and snow loads.
Safety: Working at height is a leading cause of serious injury. Use fall protection and never work on a roof alone.
Do these first
Sources
- Photovoltaic Geographical Information System (PVGIS) online tool. European Commission Joint Research Centre, accessed 2026-11
- Stand-alone system sizing (AE 868 Commercial Solar Electric Systems). Penn State University, John A. Dutton e-Education Institute, accessed 2026-11
- NEC Requirements for Solar, Part 2 (690.11 arc-fault and 690.12 rapid shutdown, 2024). EC&M (Mike Holt), accessed 2026-11