Aigeo compares SF6-free RMUs from Schneider Electric, ABB, Siemens and Eaton

Aigeo has published a buyer-focused comparison of SF6-free ring main units for secondary distribution up to 24 kV, covering switching design, retrofit fit, utility deployments and environmental documentation. The review is aimed at utility buyers weighing how quickly fluorinated-gas-free switchgear can replace legacy equipment under the EU’s 2026 rules.

Why it matters: - Utility buyers are moving toward SF6-free medium-voltage switchgear as EU rules tighten and suppliers race to prove real-world fit, not just lower emissions. - The comparison focuses on what matters in procurement: how each RMU interrupts current, whether it matches existing installations, and how environmental claims are documented. - The article highlights products that can support secondary distribution up to 24 kV without fluorinated gas insulation or interruption.

What happened: - Aigeo released a comparison of SF6-free ring main unit ranges from Schneider Electric, ABB, Siemens and Eaton. - The review covers Schneider Electric’s RM AirSeT, ABB’s SafeRing Air and SafePlus Air, Siemens’ 8DJH 24 blue GIS, and Eaton’s Xiria. - The comparison draws on manufacturer documents, regulatory texts and project announcements, and does not include independent product testing. - The review was published for utility buyers evaluating SF6-free RMUs for secondary distribution.

The details: - Schneider Electric uses Pure Air in RM AirSeT, ABB uses dry air in SafeRing Air and SafePlus Air, and Siemens uses Clean Air in sealed gas-insulated enclosures. - Schneider Electric and ABB describe their air media as having a global warming potential of zero. - Siemens specifies a global warming potential below 1 for Clean Air. - Eaton’s Xiria combines vacuum interrupters with air and solid insulation. - The named ranges use no fluorinated gas for insulation or interruption. - Article 13(9)(a) of Regulation (EU) 2024/573 prohibits putting into operation medium-voltage switchgear up to and including 24 kV that relies on fluorinated gases for insulation or interruption in the EU from 1 January 2026, subject to derogations. - The regulation lists SF6’s 100-year global warming potential as 24,300 relative to CO2. - RM AirSeT load-break switching uses Schneider Electric’s shunt vacuum interruption, or SVI, and keeps a conventional three-position switch. - Siemens’ three-position blue switch uses vacuum interruption in an auxiliary current path. - Eaton uses vacuum interrupters for Xiria load-break switches and circuit breakers. - ABB specifies dry-air puffer interruption for load-break switches and vacuum interruption for its V-module circuit breakers. - Aigeo says switching duty and endurance should be checked against type-test evidence for each functional unit offered. - Schneider Electric describes RM AirSeT as a compact RMU suited to kiosk substations. - Schneider Electric uses the same SVI switch in SM AirSeT, which fits existing SM6 cubicles with busbar and cable connection heights unchanged. - ABB says SafeRing and SafePlus Air retain the interface, footprint and operation of the corresponding SF6 products. - Siemens says 8DJH 24 blue GIS retains the compact dimensions of its SF6 counterpart. - Eaton offers compact block and extendable Xiria configurations. - Cable interfaces, foundations and extension arrangements still require site checks. - Schneider Electric publishes Product Environmental Profiles for AirSeT products on its document server, including an externally verified Type III profile under ISO 14025 for SM AirSeT. - Siemens and ABB register environmental product declarations for their switchgear with EPD-Norway. - Eaton registers Xiria declarations with PEP Ecopassport. - Aigeo says buyers should request the declaration for the exact configuration and verify its status before comparing results.

Between the lines: - Shunt vacuum interruption changes the switching architecture, not just the insulation medium, and that can affect how utilities compare performance and serviceability. - The comparison suggests that “SF6-free” is no longer enough for procurement decisions; buyers also need to know whether a product can retrofit into existing bays and whether its environmental paperwork is comparable. - The cited utility deployments show market adoption, but they are not presented as proof of comparative reliability. - Aigeo frames the decision as a match between technical switching design, installed infrastructure and environmental documentation rather than a pure product ranking.

What's next: - Utility buyers will need to line up specifications against site conditions, especially where existing cubicles, foundations or cable interfaces must be reused. - The relevant environmental declaration for each exact configuration will matter more as procurement teams compare products across different reporting schemes. - The EU switchgear ban will keep pressure on suppliers to expand SF6-free ranges and document performance clearly. - Buyers evaluating retrofit projects will likely focus on whether a given RMU preserves footprint and operating sequence while meeting local utility standards.

The bottom line: - Aigeo’s review positions SF6-free RMUs as a procurement decision about switching design, retrofit fit and verified environmental data as much as insulation medium.