BTW: The photo with the arc in the article is misleading, what you see there is a disconnector/isolator switch, it’s not used to switch loads, it’s just there to visibly disconnect circuits. The actual switches used switch loads look like T-shaped ceramic insulators. If you’d use a disconnector to switch loads you’d get huge arcs that could damage it (there are photos of that happening when the actual switch failed). The tiny arc you see in the photo is either from residual currents or electrostatic discharge.