Live-Tank outdoor vacuum circuit breakers

With our Live-Tank outdoor vacuum circuit-breakers, we provide reliable quality for all your medium-voltage network needs
Circuit-breakers form a most vital part of your medium-voltage network. They must make and break all currents within the scope of their ratings, from small inductive and capacitive load currents up to the short-circuit current, regardless of earth faults, phase opposition, etc. Outdoor vacuum circuit-breakers (OVCB) have to face even higher demands, with the additional influence of weather conditions. For its proven reliability, network operators around the world have chosen Siemens medium-voltage vacuum circuit-breakers for over 40 years, with over 350,000 vacuum circuit-breakers in service to date.
The right solutions for tomorrow’s intelligent networks
Siemens puts large effort into developing and manufacturing its medium-voltage circuit-breakers to the highest possible standards, enabling them to withstand the toughest climates and function reliably in practically every kind of environment.The space saver
The Live-Tank 3AF0 is used for transformer substations and distribution grids, where it reliably switches off overhead lines. It excels with its light-weight and space saving compact design. Moreover, it is totally restrike-free and offers reliable operation through its spring stored-energy operating mechanism.
Due to their modular structure and lightweight components, our live-tank circuit breakers 3AF0 can easily be transported to their installation site. Their switching function is based on the same, well-proven components we use for our indoor circuit breakers. In addition, they can be optimally adapted to each application using current and voltage transformers. And since they contain very few moving parts, our live-tank circuit breakers 3AF0 are virtually maintenance-free.
Tailor-made for traction power substations
The Live-Tank 3AF04 / 3AF05 for AC traction power supplies is especially designed for railway distribution networks and consists of three major parts: the pole assembly, the operating mechanism box, and the supporting steel structure. For easy access, the operating mechanism box is situated inside the supporting steel frame. It features the circuit-breaker operating mechanism including motor, release and auxiliary switches and the control cabinet. The actual switching is carried out by a vacuum interrupter mounted inside the weatherproof pole assembly at electrical potential (live). The two pole assemblies rest on a base frame with a common operating shaft.
The design of our AC traction power supply OVCBs 3AF04 and 3AF05 respectively offers all the advantages of the proven 3-pole live-tank OVCB 3AF01. It comprises a minimum number of moving parts and a simple construction, which guarantee outstanding operational reliability and mechanical endurance. All control elements have been placed in the operating mechanism box, which also contains the fully wired control cabinet for local operation of the circuit-breakers.