12kV ring main unit - Standardized design customization
(SFX-12 solid insulation)
(SFX-12 solid insulation)

Product Overview

SFX-12 series solid insulated standardized ring main unit, circuit breaker cabinet, is developed according to “The standardized Design and Customization Scheme of 12kV Ring Main Unit”, adopts the top expansion busbar form, the interface type of the primary and secondary equipment conforms to the state grid standardization requirements, with strong general interchangeability. SFX-12 series ring main unit does not need SF6 gas, reduces the damage to the atmosphere, with significant ecological benefit, it is the future direction of environmentally-friendly electrical equipment. SFX series solid insulated medium is less affected by altitude and humidity, ring main unit in high altitude, condensation prone areas show its superior electrical performance. EFX series standardized ring main unit is mainly used in the housing and distribution projects of the State grid, and is also suitable for the transformation of power system urban network, power distribution station and load center power station, petrochemical industry, steel and mining industry, general enterprises and institutions, high-rise buildings, etc.

Main technical parameters

Project UnitCircuit breaker cabinet
Rated voltagekV12
Power frequency withstand  voltage(1min)Phase to phase and phase to  groundkV42
Between open contactskV48
Lightning impulse withstand  voltagePhase to phase and phase to  groundkV75
Between open contactskV85
Rated frequencyHz50
Rated currentA630
Rated short-circuit  breaking current kA20
Rated short-time withstand  current 


Rated peak withstand  current kA50
Annual leakage rate≤0.1%
Arcing test20kA 1s
Protection gradeAir boxIP 67
Ring main unitIP 4X


 Top expansion