The history
About 175 years from a thin wire that melted on purpose to the row of MCBs and the RCCB in every new Indian home.
As soon as electric current flowed through buildings, people learned that too much of it starts fires. The first answer was a deliberately weak link, a fuse, that melted before anything else could. Then came switches that trip themselves and can be reset, devices that notice current leaking through a person, and research on how much current the human body can survive. In India, rules and standards slowly caught up, from the Indian Electricity Act of 1910 to the National Electrical Code 2023, while electrocution still kills thousands every year.
by 1864
Fusible wire protection in use
Telegraph and lighting engineers
1879
Circuit breaker described in a patent application
Thomas Edison, USA
1924
Thermal-magnetic miniature circuit breaker
Hugo Stotz and Heinrich Schachtner, Germany
1955–56
High-sensitivity earth-leakage breaker
Henri Rubin, South Africa
1985
India's National Electrical Code
Indian Standards Institution (BIS)
1840 – 1920
Telegraphs and the first electric lights are protected by thin wires that melt when the current gets too big.
1847
mid-1800s
Telegraph engineers found that lightning and faults could burn out their equipment. Louis Breguet is credited with suggesting a short piece of thinner wire that would melt first. By 1864 fusible wires and foils were in use on telegraph lines and in lighting installations.
Why it mattered. The idea of a deliberate weak link that sacrifices itself is still the heart of every fuse.
1882
4 September 1882
Edison's Pearl Street Station began supplying DC electricity to customers in lower Manhattan. Branches of the wiring were protected by fuses that melted if a circuit drew too much current.
Why it mattered. It showed that a city-wide network needed protection built in at every branch, as your distribution board has today.
1890
Edison received a patent for a fuse as part of his electric distribution system. Screw-in plug fuses became the standard protection in American homes for decades.
Why it mattered. Fuses became cheap, standard parts that any home could have.
1879 – 2024
Edison sketches an automatic breaker; in 1924 a German inventor puts a bimetal and an electromagnet in one small, resettable switch.
1879
While designing a complete system to light homes and streets, Edison described an early form of automatic circuit breaker in an 1879 patent application. His commercial system of the 1880s used fuses instead, because they were simpler and cheaper.
Why it mattered. It was the first idea of a switch that opens itself when current gets too high.
1924
November 1924
Hugo Stotz, whose company had been bought by Brown, Boveri & Cie in 1918, worked with his chief engineer Heinrich Schachtner on a small breaker that could replace a screw-in fuse. It combined a thermal trip for overloads and a magnetic trip for short circuits, and could simply be switched back on. It was patented in 1924 (German patent 458392).
Why it mattered. It is the direct ancestor of the MCBs in your distribution board: two trips in one resettable switch.
2024
A hundred years after Stotz's patent, ABB, the company that grew partly out of Brown, Boveri & Cie, said it had made more than a billion miniature circuit breakers and was producing over 100 million poles a year.
Why it mattered. A small switch invented in 1924 now guards homes all over the world.
1910 – 2011
Laws, codes and standards set what an installation and a breaker must do, in India and worldwide.
1910
The Indian Electricity Act of 1910 set rules for licensing electricity supply and for safety in the young industry. It stayed in force, with the Electricity (Supply) Act of 1948, until the Electricity Act of 2003 replaced them.
Why it mattered. It was the legal root of every later Indian rule about safe wiring.
1956
The Indian Electricity Rules, 1956, made under the 1910 Act, set detailed safety rules for installations: earthing, insulation, clearances and protection. Electrical inspectors used them for more than fifty years.
Why it mattered. They were India's main wiring safety rules until the CEA regulations of 2010 replaced them.
1987
IEC 898 set out how household circuit breakers up to 125 A must behave. Later editions, renumbered IEC 60898-1, fix the B, C and D instant-trip bands and the 1.13 and 1.45 times rating tests, and India adopted it as IS/IEC 60898-1.
Why it mattered. It is why an MCB bought anywhere follows the same kind of trip curve.
2003
The Electricity Act of 2003 replaced the 1910 and 1948 Acts. It gave the Central Electricity Authority the power to make safety regulations for the whole country.
Why it mattered. It set up the framework that today's safety regulations come from.
2008
IS 12640-1:2008 set out how household RCCBs must work, in line with IEC 61008-1. For example, a 30 mA device must trip within 300 ms at 30 mA and within 40 ms at 150 mA.
Why it mattered. It fixes the trip times that make an RCCB a life-saver.
2010
20 September 2010
The Central Electricity Authority (Measures relating to Safety and Electric Supply) Regulations, 2010, came into effect in place of the 1956 Rules. They covered earthing, protection and the inspection of installations across India.
Why it mattered. Safety rules were updated for modern wiring and devices.
1928 – 1990
Engineers learn how little current it takes to kill, and build devices that trip on a leak of a few milliamps.
1928
An engineer at the German power company RWE was granted a patent for a protective circuit that would disconnect the supply when a person or an animal touched a live conductor. A residual current circuit for detecting earth faults had been patented by Schuckert in 1903 (attributed).
Why it mattered. The idea of comparing currents to protect people, rather than wires, was born decades before it became practical.
1943
1940s–1961
Professor Charles Dalziel ran careful tests on volunteers to find the current at which people could no longer let go of a live conductor. He reported an average let-go current of about 16 mA for men and about 10.5 mA for women at 60 Hz, and later estimated the currents that could stop the heart.
Why it mattered. His numbers are why protection against shock is set at milliamps, not amps.
1955
1955–1956
Henri Rubin built an earth-leakage protection system that could detect small leaks, first for mines. By early 1956 his prototype, rated 220 V and 60 A, tripped at about 12.5 to 17.5 mA.
Why it mattered. It is widely considered the first high-sensitivity device able to protect a person who touches a live part.
1961
Dalziel turned his research into a transistorised device that compares the currents in the two wires and cuts the power on a small difference. In North America it is called a GFCI; elsewhere, an RCD or RCCB.
Why it mattered. Leakage protection became a small, affordable device for ordinary homes.
1974
1970s (attributed)
The IEC gathered animal studies, accident reports and volunteer tests into one guide to the effects of current on the body, now IEC 60479-1. Its chart splits current and time into zones, from 'not felt' to 'the heart may fibrillate'.
Why it mattered. It is the chart that tells engineers a 30 mA device tripping within 40 to 300 ms keeps people safe.
1985 – today
Rewireable fuses give way to MCB boards with RCCBs, and new codes and regulations make leakage protection the norm.
1985
The National Electrical Code of India (SP 30) was first formulated in 1985. It gathered in one place the good practice for wiring homes, offices and factories, pointing to the Indian Standards for each part.
Why it mattered. It gave electricians and inspectors a shared rule book for safe installations.
1987
Havells began making miniature circuit breakers at Badli in Delhi in a joint venture with the German firm Geyer. Several Indian makers followed, and MCB distribution boards slowly replaced rows of porcelain rewireable fuses.
Why it mattered. Local manufacturing made resettable breakers affordable for Indian homes.
1996
1990s
Many older Indian homes used porcelain 'kit-kat' rewireable fuses, often 'repaired' with whatever wire was handy, which made them useless. An Indian MCB standard (IS 8828, based on IEC 898) and cheaper boards pushed new homes towards MCBs, which trip at the right current every time.
Why it mattered. A breaker cannot be bodged with thicker wire, so the protection stays what it was designed to be.
2018
1987, revised 2018
IS 3043, India's code of practice for earthing, was first published in 1987 and revised in 2018. It describes pipe and plate electrodes, earth conductors and how to measure earth resistance.
Why it mattered. Good earthing gives a fault current a safe path and lets protective devices do their job.
2022
NCRB's Accidental Deaths & Suicides in India report recorded 12,918 people killed by electrocution in 2022, about 35 a day, most of them men. The figure covers every setting, including farms, streets and workplaces, not only homes.
Why it mattered. It is why leakage protection, good earthing and trained electricians matter so much.
2023
6 January 2023
BIS released the second revision of the National Electrical Code, SP 30:2023, bringing Indian practice in line with current international standards.
Why it mattered. It is the rule book a licensed electrician should follow when wiring your home today.
2023
8 June 2023
The CEA (Measures relating to Safety and Electric Supply) Regulations, 2023, replaced the 2010 version. Among many rules, they call for residual current protection of not more than 30 mA in domestic installations.
Why it mattered. Leakage protection for people became a clear national expectation for homes.
By the numbers
People killed by electrocution in all settings, as recorded by the National Crime Records Bureau. Reporting varies by state, so treat these as lower bounds.
Did you know?
An MCB must carry 1.13 times its rating for a whole hour without tripping, but trip within an hour at 1.45 times (IS/IEC 60898-1).
A 30 mA RCCB must trip within 40 milliseconds when 150 mA leaks: quicker than a blink.
The same 16 A MCB that ignores 0.1 A through a person trips in a few milliseconds on a 400 A short circuit.
An arc chute chops one arc into a dozen or more little ones, each needing about 20 V to keep burning.
In 2022 India recorded 12,918 deaths from electrocution, about 35 a day (NCRB).
The people
1847 – 1931 · Inventor and businessman · USA
Built the first central power system protected by fuses and described an early circuit breaker.
c. 1869 – 1935 · Inventor and entrepreneur · Germany
Credited with the first miniature circuit breaker, patented in 1924.
20th century · Chief engineer, Stotz-Kontakt · Germany
Worked with Stotz on the thermal-magnetic MCB.
20th century · Engineer · South Africa
Built the first high-sensitivity earth-leakage protection system in 1955–56.
1904 – 1986 · Professor of electrical engineering · USA
Measured let-go currents on volunteers and developed the ground fault circuit interrupter.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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