In 1901, a fire station in Livermore, California, installed a standard hand-blown light bulb. Well over a century later, that exact same bulb is still burning. Recognized by the Guinness Book of World Records as the oldest operating light bulb on Earth, the Centennial Light has survived station relocations, renovations, and the invention of modern electrical grids.
Its uninterrupted glow outlasted the company that manufactured it and continues to puzzle experts. It now operates continuously under the watchful eye of a dedicated webcam and a specialized power supply.
A Shelby Electric Creation
French engineer Adolphe Chaillet originally invented the carbon-filament socket technology used to create this device. The Shelby Electric Company in Ohio manufactured the handmade bulb in the late 1890s.
In 1901, Dennis Bernal sold the Livermore Power and Water Company and donated this 60-watt bulb to the local fire department. It was first installed in a hose cart house on L Street. As the fire and police departments expanded, they relocated the bulb to a downtown garage.
Surviving Relocations and Renovations
The bulb remained turned off for about a week in 1937 during a station renovation. Decades later, a reporter named Mike Dunstan investigated local rumors and confirmed its extreme age in a 1972 newspaper article. When the fire department moved to Fire Station #6 in 1976, they took extreme precautions to protect the fragile antique.
Fearing the glass would break, crews severed the cord instead of unscrewing the socket. Escorted by a full fire truck procession, the bulb traveled in a custom box and lost electricity for just 22 minutes.
The Science Behind the Glow
The device owes its extreme longevity to a few specific manufacturing and environmental factors. Handcrafted construction with a thick carbon filament makes it much stronger than modern tungsten alternatives. The glass envelope also contains a high nitrogen atmosphere.
Crucially, the bulb is rarely turned off. Skipping the constant heating and cooling cycles of flipping a switch prevents severe temperature stress on the components. While it started at 60 watts, the output has decreased significantly. Today, it emits a dim glow equivalent to a 4-watt nightlight.
A Rare Modern Blackout
The light has run on an uninterruptible power supply for decades, but it experienced a brief blackout in May 2013. Viewers watching the live webcam noticed the video feed go dark. An electrician arrived the next morning and discovered the bulb had not burned out.
The dedicated power supply had failed. Crews bypassed the faulty equipment with a standard extension cord, restoring the light after nine hours and forty-five minutes of darkness. The Livermore-Pleasanton Fire Department plans to maintain and house the bulb indefinitely.