What is the dielectric strength of a vacuum interrupter compared to SF6 gas?

The correct choice indicates that the dielectric strength of a vacuum interrupter is four times greater than that of SF6 gas. This is significant because it highlights the advantages of vacuum technology in interrupting electrical currents.

In a vacuum, there are no particles or molecules that can assist in the breakdown of the insulating medium under high voltage, which allows for a very high dielectric strength. Conversely, SF6 gas, while an excellent insulator and widely used in electrical equipment, has physical properties that limit its dielectric strength compared to a vacuum.

The superior dielectric strength of a vacuum interrupter means that it can operate safely at higher voltages and while handling fault currents more effectively, leading to more compact designs and improved performance in power systems. This property makes vacuum interrupters particularly advantageous for high voltage applications, where space and reliability are critical.