What conditions must be met for ignition from an electrical source to occur?

Ignition from an electrical source occurs when there is sufficient heat produced from energized wiring. This means that for electrical sources to ignite materials, the wiring must generate enough thermal energy to raise the temperature of nearby combustible materials to their ignition point. When energized, wiring can create heat due to electrical resistance, friction, or short circuits. If this heat is substantial and persistent, it can cause combustibles in proximity to ignite.

The other conditions listed are not conducive to ignition. Proper grounding and insulation help prevent faults and protect against electric shock but do not directly contribute to the ignition process itself. Additionally, if the electrical source is de-energized, it obviously cannot produce heat or cause ignition. Lastly, while keeping combustible materials at a safe distance from electrical wiring is a good fire prevention practice, this does not play a direct role in the ignition caused by energized wiring, which is the focus of this question.