Sealed Stainless Steel Gas Tank for 12kV Urban Distribution
The 10kV / 12kV distribution level carries the majority of the world's urban electricity supply to end users. At this voltage level, the practical constraint is not electrical performance but installation environment: switchgear ends up in transformer kiosks on pavements, in the basements of high-rise buildings, on rooftop electrical decks, and inside prefabricated substations sited on the far edge of a factory. All of these are difficult places to run a maintenance programme. Sealing the primary live parts inside a 3mm 304 stainless steel gas tank makes the switchgear maintenance-free by design — the tank interior is not accessible in service and does not need to be, so the switchgear can be installed and forgotten.
Compact Footprint for Kiosk, Basement and Prefab Installations
The physical footprint is engineered for space-constrained installations. Distribution transformer kiosks and high-rise building substation rooms are typically dimensioned around the transformer, with the switchgear fitting in whatever remains. The compact tank layout leaves room for cable termination access and door swing in installations that would not accommodate an air-insulated cabinet of equivalent rating. Modular C / F / V unit combinations mean the exact feeder mix required by the single-line diagram is delivered without oversized cabinet volume.
3mm 304 Stainless Steel Tank, Laser-Welded on TRUMPF Systems
The gas tank is built from 3mm 304 stainless steel plate and welded on 3D five-axis laser welding systems imported from TRUMPF (Germany). Laser welding gives a narrow uniform seam with much lower heat-affected zone distortion than conventional MIG or TIG welding, which translates directly into better long-term gas tightness. The finished tank has a smoother external appearance without post-grinding — an important detail on installations where the switching station is visible to the public, such as pavement kiosks and campus substations.
Verified ≤0.01% Annual Gas Leakage — 30-Year Service Life
Every finished tank is leak-tested on a SEILER (Germany) automatic helium leak detection line. Helium mass spectrometry can detect leak paths several orders of magnitude smaller than pressure-decay methods, so the ≤0.01% per year annual leakage rating is a verified factory number, not an extrapolation. The tank normal service life exceeds 30 years, so a switchgear installed today in a distribution kiosk should carry out its full service life without gas top-up.
Fully-Insulated Solid Extension Busbar
Extension busbars use fully-insulated screened solid busbar construction. Every conductive surface is covered by a bonded insulation layer with an outer earthed screen, so the busbar surface can be safely handled during connection work and there is no exposed live metal even when a tank is open. This matters on urban distribution installations where the switchgear sits in cramped spaces and the operator is close to the equipment during commissioning and future extension work.
1750A Load-Break Switch – Fuse Combination Transfer Current
The load-break switch – fuse combination unit at 12kV is rated at a transfer current of 1750A. Transfer current is the current level up to which the load-break switch can safely commutate the feeder onto the fuse element without arc restrike, so a high transfer current rating widens the range of feeder loads (typically distribution transformers) that can be protected through the fuse combination. A 1750A rating covers all practical distribution transformer ratings on a 12kV distribution feeder.
AFLR 20kA / 0.5s Internal Arc Classification with IP54 / IK10 Switching Station
Internal arc classification is AFLR 20kA / 0.5s — accessibility on Front (A), Lateral (L) and Rear (R) verified for a 20kA arc fault sustained for 0.5 seconds. At the switching-station level (the complete installation including cabinet and mounting), protection reaches IP54 against dust and water ingress, with IK10 mechanical impact protection. This is the rating combination expected of an outdoor pavement kiosk or a rooftop switching station exposed to weather and possible impact.
Automation-Ready Design and Fully-Automated Assembly Line
The platform supports a factory-integrated automation package, so an intelligent switch concept (remote status, motorised operation, condition monitoring) can be delivered as part of the panel rather than added on-site. All cabinets are built on a fully-automated assembly line, so unit-to-unit dimensional variance is measured rather than estimated. On a large urban distribution rollout — where hundreds of identical RMUs are deployed across a city — this predictability is a direct saving in commissioning and future spare-parts management.
