What is the main purpose of the oil in an oil circuit breaker?

The main purpose of the oil in an oil circuit breaker is to quench the arc. When the circuit breaker operates, particularly during the interruption of current flow, an arc may form between the contacts. The oil surrounding the contacts plays a critical role in extinguishing this arc. The unique properties of the oil, such as its cooling and insulating capabilities, help to absorb the heat generated by the arc and thereby limit its duration, preventing damage to the circuit breaker and maintaining circuit integrity.

The oil also serves secondary functions such as providing insulation to electrical components, but its primary role in the context of arc quenching is paramount. This characteristic is especially important in high-voltage applications where the possibility of large and sustained arcs can present serious risks. The effective quenching of the arc ensures safe and reliable operation of the electrical system.