AS/NZS Solar PV
Ground-mounted arrays involve longer DC runs and different thermal conditions than rooftop installations.
Ground-mounted solar arrays differ from rooftop installations in two ways that matter directly for DC cable sizing: run length and thermal environment.
A ground-mounted array is often positioned some distance from the building's inverter and switchboard location — sometimes tens of meters. Since DC circuits carry a tighter voltage drop limit than general AC circuits (commonly 1–3%), a longer run makes that tighter limit meaningfully harder to satisfy without upsizing the conductor.
A ground-mounted array's cable often runs underground in conduit, or above ground shaded by the panels themselves — a genuinely different thermal environment from a rooftop cable baking in direct sun. Underground conduit runs bring their own correction factors related to soil thermal resistivity and burial depth, distinct from the rooftop-temperature corrections covered elsewhere.
A ground-mounted array frame typically needs its own dedicated earth electrode, bonded back to the main earthing system — rather than relying solely on a building's existing earth reference, which is further away and adds loop length.
Work through your ground-mount array's actual run length and conditions in the AS/NZS PV/Solar DC Cable Sizing calculator.
Engr. Jason Morales — Founder, SolarEnergyPH & OhmWorks