Solar rooftop fires are typically brought on by design errors, component failures, and improper installation. According to Energy Efficiency & Renewable Energy, these issues can result in hot spots that can ignite surrounding flammable materials, arcs between conductors or to the ground, and other electrical system-related hazards.
Electric arcs are a leading reason for a solar fire because they occur when electrical energy passes through an air gap via ionized gas molecules, causing the air molecules to disintegrate into their ionized constituents (referred to as a “plasma”). This causes a large current to flow into whatever is nearby.