Circuit Breaker Manufacturing: From Fuses to ABB Robots

Circuit breaker manufacturing is a quiet industry with huge volumes. Almost every home, school and hospital has a row of breakers behind a panel door, and each one has to switch off a fault on demand, every time, for decades. In September 2026 ABB reported that its Santa Palomba plant near Rome had built its 100 millionth residual current circuit breaker. This post follows how circuits were protected before breakers, how the miniature breaker took over, and how robots now assemble and test these devices. It also covers where ABB robots such as the IRB 1200 and YuMi fit.

An open knife switch with its exposed blade and porcelain base. Photo: AYL / Wikimedia Commons (CC BY-SA 3.0)

Knife switches, fuses and a better idea

Early electrical equipment was controlled with knife switches, a metal blade hinged into spring jaws. The blade and jaws were fully exposed, so a careless hand risked shock, and opening one under load could throw an arc that burned the operator. As voltages rose, open switches gave way to enclosed safety switches. A switch only turns current on and off by hand, though. It does nothing when a wire overheats, so wiring needed a second device that acted on its own and cut the circuit before a hot wire started a fire.

Two screw-in plug fuses, one marked Moss-Schury. Photo: Gazebo / Wikimedia Commons (CC BY-SA 4.0)

That device was the fuse. Thomas Edison described an early form of circuit breaker in a patent application in 1879, but his lighting system used fuses, and fuses won the first decades of practice. A thin metal element melts when the current is too high and the circuit opens. It is cheap and reliable, with one drawback: it destroys itself. After every overload someone had to find the right replacement and screw it in, and a fuse once blown could not be reused.

Edison base plug fuses, one of them a time delay type. Photo: Gazebo / Wikimedia Commons (CC BY-SA 4.0)

The fix came from Mannheim. Hugo Stotz founded his firm there in 1891, sold it to Brown, Boveri & Cie around 1918 and stayed on as managing director. ABB dates the patent for his miniature circuit breaker to November 1924, though some sources say 1923. It combined thermal and magnetic tripping in one resettable unit, and it could be screwed into existing fuse sockets. Serial production began in 1928. After a fault the owner could reset it with a lever instead of buying a new fuse.

An ABB S201 B16 miniature circuit breaker, a descendant of the 1924 Stotz design. Photo: VoltCrafter / Wikimedia Commons (CC BY-SA 4.0)

Where ABB robots fit in a breaker factory

The latest news comes from Santa Palomba. In September 2026 ABB said the plant, which opened in the early 1980s, had reached 100 million residual current circuit breakers. These devices disconnect within milliseconds when they detect earth leakage current. ABB's story concentrates on energy: more than 3,000 solar panels on nearby warehouse roofs, LED lighting and heat pumps, which together cut emissions by around 720 tonnes a year. It does not say how the lines are automated, so we should not guess at the robots there. The open floor plan, ABB adds, lets production layouts change without major structural work, which matters for any plant that keeps adding product versions.

Open production floor at ABB's Santa Palomba plant near Rome, where the 100 millionth RCCB was built. Photo: ABB

Other ABB sites do say. At its Rakovski factory in Bulgaria, which reached its 100 millionth miniature circuit breaker in 2019, ABB said its testing lines were engineered in Germany and that ABB robots automatically test components against key performance metrics before they leave. The site makes over 4,000 versions of miniature breakers. In Vaasa, Finland, the integrator JOT Automation built a robotic switchgear assembly line for ABB Smart Power. Pick and place work like this suits compact arms such as the IRB 1200.

The robotic switchgear assembly line JOT Automation built for ABB Smart Power in Vaasa, Finland. Photo: ABB

Assembly is hard to automate for good reasons. A single phase breaker has around 33 individual parts, according to the machine builder STIWA, and each one must be fed, placed and checked. Slovenian maker ETI describes a residual current breaker line of 15 machines linked by manipulators and conveyors. Robots earn their place at the handoffs and test stations. Teams usually prove such cells in a simulator like RobotStudio before any hardware moves, and a dual arm YuMi IRB 14000 is a possible fit for the smallest parts.

ABB's Rakovski team in Bulgaria with the display for the plant's 100 millionth miniature circuit breaker in 2019. Photo: ABB

What comes next for breakers and the lines that build them

The breakers themselves are changing. ABB's new direct current portfolio for AI data centers, announced in September 2026, shows demand moving toward DC systems and higher power, and ABB has also published a piece on how changing power requirements shaped a new generation of low voltage switchgear. Direct current is harder to interrupt than alternating current, because it has no natural zero crossing to help extinguish the arc. New designs will need new test routines, and those routines will in turn need new robot test cells.

The Santa Palomba team outdoors at the plant after the 100 millionth residual current breaker, September 2026. Photo: ABB

For homes, the basic job stays the same: trip fast on a fault and reset easily. If makers add measurement and communication to the breaker itself, which is a possibility rather than an announcement, each unit would carry more electronics and more parts. That would make assembly harder for people and better suited to precise machines that place every part the same way. Our overview of ABB robot use cases shows the wider range of work these arms already do, from small parts handling to testing and packing.

Close-up of an ABB robot picking parts in a switchgear assembly cell. Photo: ABB

Open problems remain on the factory floor. Product variety is huge, so cells must change over quickly between versions. Flexible grippers cost money, and skilled technicians are needed to program and maintain them, a gap that training and simpler tools such as Wizard easy programming may help to close. Testing every breaker means handling live voltage, so safety design matters as much as speed. Even so, the pattern is clear, and ABB's own plants show it. Fuses once failed by melting and were replaced by hand, while today a breaker is built and checked by machines long before it ever sits in a panel.

An ABB robot assembling switchgear parts on the Vaasa line. Photo: ABB

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