What’s the difference in the circuit breaker for air - insulated vs gas - insulated?

Insulation Performance：

• Air - insulated Circuit Breakers: They use air as the insulating medium. The insulation performance of air is relatively limited. In harsh environments such as high humidity and high pollution, the insulation performance is easily affected. They are suitable for medium - and low - voltage applications.
• Gas - insulated Circuit Breakers: Commonly, gases such as sulfur hexafluoride (SF6) are used. They have excellent insulation performance and can withstand higher voltages, making them suitable for high - voltage scenarios. For example, under the same pressure, the insulation strength of SF6 gas is more than three times that of air.

Arc - Extinguishing Ability：

• Air - insulated Circuit Breakers: Arc - extinguishing mainly relies on compressed air blowing to cool the arc, and the arc - extinguishing ability is relatively weak.
• Gas - insulated Circuit Breakers: For SF6 circuit breakers, SF6 gas has a strong arc - extinguishing ability. It can quickly extinguish the arc, and the breaking capacity is strong.

Structure and Volume：

• Air - insulated Circuit Breakers: The structure is relatively simple. However, to ensure the insulation distance, the volume is usually large.
• Gas - insulated Circuit Breakers: Due to the good insulation performance of the gas, the required insulation space is small, so the structure is more compact and the volume is smaller.

Environmental Adaptability：

• Air - insulated Circuit Breakers: They are relatively sensitive to environmental humidity, pollution, etc. In harsh environments, additional protective measures are required to ensure performance. However, they also have an advantage in environmental adaptability and can operate under a variety of environmental conditions.
• Gas - insulated Circuit Breakers: SF6 and other gas - insulated circuit breakers need to be used in a dry and clean environment to maintain the stability of the gas performance. However, dry - air - insulated switchgear that has emerged in recent years has improved environmental adaptability to a certain extent.

Maintenance and Cost：

• Air - insulated Circuit Breakers: The manufacturing cost is relatively low, but the contact wear is relatively fast, and the service life is relatively short. The contacts need to be replaced regularly.
• Gas - insulated Circuit Breakers: The price of SF6 gas is high, and special storage and handling equipment are required, resulting in high initial costs. Regular inspections of gas pressure, leakage, etc. are also needed, so the maintenance cost is relatively high. However, the service life is long, and the long - term comprehensive cost may be reduced due to less maintenance.