First, the atmospheric pressure fully sealed system shields the RMU from external effects and guarantees stable operation. Second, the switchgear's single-phase insulating interior eliminates risks of internal arcing explosion. Third, the insulating medium inside the cabinet is air of atmospheric pressure which prevents the insulation performance from being weakened by pressure leak during the service life.

In China, the atmospheric pressure sealed nature-air insulated RMU has become a widely adopted solution within the power distribution networks of the country's two largest state-owned grid companies: State Grid Corporation of China (SGCC) and China Southern Power Grid (CSG). Since its inclusion in their procurement catalog in 2017, the air insulated RMU has been recognized as a standard product with both corporations making large-scale purchases each year. This marks a significant step forward in its adoption across the country, reinforcing its role as a reliable and environmentally friendly option for modern power distribution.

The RMU can be mounted against the wall and 80 cm of space should be preserved in front of the cabinet for installation. The switchgear adopts lower incoming and lower outing of cable.

Combining switchgears of different brands is not advised, as they vary in plug and circuit and combining them may result in risks.

An Atmospheric Pressure Sealed Nature-Air insulated Ring Main Unit (ASNA RMU) is a power distribution unit where the main electrical components are housed in a sealed cabinet, using air at atmospheric pressure as the primary medium of insulation. The design of this switchgear ensures a leak-proof, fully insulated and low maintenance operation, with key components like the vacuum interrupters, load break switches, and bus-bars enclosed safely. With their fully enclosed and insulated construction, RMUs minimize the risk of electrical faults, providing enhanced safety in environments for industrial, commercial, and residential applications where reliability and protection are critical. With over 50,000 units operating worldwide for over a decade with proven safe stable and fault-free performance, this power distribution unit works without SF6, complying with the international trend. SF6 free switchgear leads the development of sustainable RMU technology.