Why is an oil switch considered to extinguish arcs better than an air switch?

An oil switch is considered to extinguish arcs better than an air switch primarily because oil acts as an insulator. When an electrical arc occurs in a switch, the arc generates high temperatures and can create a conductive pathway, which can prolong the arc or make it difficult to interrupt. The presence of oil around the conductors helps to quench or extinguish the arc effectively.

Oil is a dielectric medium, meaning that it has excellent insulating properties. This feature allows it to break down and absorb the energy of the arc faster than air, thereby reducing the duration of the arc and preventing the arc from sustaining itself. In contrast, while air has limited insulating capability, it can become ionized at high temperatures and voltages, allowing arcs to persist.

Additionally, while the coolant properties, boiling points, and conductivity of oil might play roles in the overall performance of oil switches, the primary advantage remains its superior insulating qualities. This is what enables oil switches to handle high-voltage applications with a higher degree of safety and efficiency compared to air switches.