SM66 type 36kV 40.5kV air insulated Ring Main Unit (RMU)

ROCKWILL SM66 type 36kV / 40.5kV air insulated Ring Main Unit (RMU) is modular metal-enclosed medium voltage switchgear for 36kV distribution system with rated maximum voltage 40.5kV. It uses atmospheric air as insulating medium, fitted with high-performance load break switch and optional fuse combination unit for transformer protection. The product complies with IEC 62271-1:2017, IEC 62271-103:2019 and IEC 62271-200:2021. Relevant documents include Type Test Certificate No. TT-2025-04135, Witness Test Report No. WT-2025-09069, Routine Factory Test Report No. FT-2025 series, Raw Material Mill Certificates, all issued by CNAS accredited independent high voltage test laboratory and available for tender submission, utility review and project site acceptance. Manual or motorized operating mechanisms are optional, together with fault indicators and communication modules for distribution automation. Tropical anti-corrosion coating can be supplied to adapt to high humidity, heavy rainfall and coastal salt mist tropical environments.