Tesla’s Method: Preventing Lightning with a Smooth, Rounded Protector
Nikola Tesla, a visionary inventor and pioneer of modern electricity, revolutionized the way we understand electromagnetism and energy. Best known for his role in advancing alternating current (AC) systems and innovations like the Tesla coil, he earned the title of “master of lightning”.
In 1916, Tesla redefined lightning protection by challenging Franklin’s rod. He introduced the Tesla lightning protector, designed to prevent air ionization and stop strikes rather than attract them, offering a safer and more proactive solution.
Today, lightning strikes increasingly threaten modern infrastructure—equipped with sensitive electronics like IT systems, telecom networks, and sensors—causing surtensions, fires, and blackouts costing billions annually. With strike frequency rising globally due to the systematic installation of capture-based lightning rods (recommended by international standards) and rapid infrastructure growth, Tesla’s forward-thinking design offers a safer, more sustainable solution. Learn how Tesla’s method prevents lightning strikes and why it outperforms conventional systems.
Nikola Tesla in his Colorado Springs laboratory, surrounded by giant electrical arcs, showcasing his experiments with high-frequency currents and wireless energy in 1899. (Photo from Tesla Museum)
Tesla vs. Franklin – Prevention vs. Attraction
For nearly three centuries, humanity has relied on a single approach to protect structures from lightning: attracting it with pointed metal rods. Since Benjamin Franklin invented the lightning rod in 1752, this capture-based method has been universally adopted, dominating global standards and markets—despite the significant damage it often causes.
Franklin’s pointed rod design, introduced in 1752, aimed to attract and ground lightning strikes. (Illustration from the 18th century)
Over a century ago, Nikola Tesla studied this phenomenon and exposed the flaws of Franklin’s approach, arguing that pointed rods attract lightning to the buildings they are meant to protect:
“It attracts lightning, so that it will be struck oftener than would be the building if it were not present.” — Nikola Tesla, U.S. Patent No. 1,266,175
As a lightning protection professional, I was stunned by Tesla’s assertion. Having worked for years following conventional capture standards, I assumed these devices simply intercepted lightning—never imagining they could trigger a strike that might not have occurred without the capture device in place.
This claim was shocking: a technology meant to protect could, in fact, create the very danger it aims to prevent. It sparked my curiosity, driving me to investigate why Tesla believed pointed rods increased strike risks, revealing a critical flaw in the capture-based approach.
Tesla’s original lightning protector drawing from the Electrical Experimenter, 1918, featuring an ellipsoidal smooth terminal, the inspiration for SPIN.
By contrast, Tesla offered a groundbreaking alternative: a preventive lightning protector with a large, rounded terminal that repels strikes by blocking the conditions that cause them. This ingenious design promises to prevent ordinary accidents, delivering unmatched safety and redefining lightning protection by challenging the very idea of triggering a strike.
Charge Density: Tesla’s Method to Prevent Corona Effects and Lightning Strikes
Key Concept: Charge Density
The quantity of electricity per unit area, measured in C.G.S. units (centimeter-gram-second system, a historical unit of charge). High charge density on sharp points makes air conductive, while low density on large surfaces prevents discharges.
In his 1918 patent (US Patent 1,266,175), Nikola Tesla noted that traditional Franklin rods, due to their sharp points, actually increase the risk of strikes by creating hazardous charge concentrations.
He introduced charge density as a key parameter,—which he defined, building on Coulomb’s work, as the quantity of electricity per unit area, or “electrical density.” A Franklin rod’s sharp point concentrates charges, creating a high density that triggers what Tesla called ionization:
“The property of points or sharp edges to give off electricity into the air.” — Nikola Tesla, U.S. Patent No. 1,266,175
Electric charge distribution comparison: sharp edges (Franklin Rod) concentrate charges, while smooth surfaces (Tesla protector) distribute them evenly. (LPS Pacifica)
A key distinction between a Franklin rod and the shape of Tesla’s dome lies in how they manage electric charges.
A sharp-pointed terminal, like the Franklin rod, concentrates electric charges at its tip due to its small surface area and high curvature, creating an intense localized electric field. This field can easily ionize the surrounding air, triggering streamers and increasing the likelihood of a lightning strike.
In contrast, the smooth Tesla dome optimizes charge distribution, creating a much more controlled electric environment. Its large surface area allows for greater charge accumulation while minimizing excessive concentrations. This prevents abrupt electric field variations and reduces the risk of premature ionization.
IEC 60052 Sphere Gap Method: A sharp rod triggers corona at 24 kV, while a 250 mm sphere delays it to 45 kV, confirming Tesla’s approach. (LPS Pacifica)
Tesla’s analysis is confirmed by modern science through the IEC 60052 Sphere Gap Method. This standard shows that spherical shapes distribute charges uniformly across their surface, significantly reducing charge density. The larger the sphere, the more the corona effect is delayed: a sharp rod triggers corona at 24 kV, while a 250 mm sphere delays it to 45 kV—a 1.9x increase—proving Tesla’s insight that rounded surfaces prevent premature discharges.
This represents a massive shift in lightning protection approaches. As Tesla warned:
“By rendering the air conductive… it is sometimes the cause of damage to neighboring objects.” — Nikola Tesla, U.S. Patent No. 1,266,175
Two palm trees struck by lightning just a few meters from an ESE lightning rod system in a public park in Da Nang, Vietnam, highlighting the capture failure Tesla warned about. (LPS Pacifica)
This remark also struck me deeply. Indeed, I regularly witness capture failures on the field, such as the case attached: two palm trees struck by lightning just a few meters from an ESE lightning rod system, demonstrating how these devices can fail to intercept strikes, causing nearby damage.
Sharp points, by prematurely ionizing the air and making it conductive, can trigger nearby lightning strikes. Delaying this phenomenon is critical to prevent such risks and enhance safety.
Spherical shapes don’t just delay the corona effect—they also significantly increase resistance to electrical arcs. The IEC 60052 Sphere Gap Method reveals that a sphere-sphere setup, compared to a sphere-point setup, requires a much higher breakdown voltage to form an arc, further validating Tesla’s approach.
Definition: “Breakdown Voltage” is the critical value at which an electric arc forms between the electrodes, sparking a connection through the air. 📖
Breakdown Voltage Test: Sphere-point (51 kV) vs Sphere-sphere (120 kV), Sphere Gap, IEC 60052. Conditions: Temp 20°C, humidity 11 g/m³, pressure 101.3 kPa, gap 80mm, AC test. (LPS Pacifica)
⚡ Striking Fact: This test reveals that a simple metal sphere with a 250mm diameter resists arc formation by nearly 2.5 times (from 51 kV to 120 kV)—a massive difference in lightning prevention.
Beyond the Sphere: As you’ve seen, Tesla’s terminal isn’t just a 250mm metal sphere. Its ellipsoidal shape significantly boosts arc resistance, requiring a much higher voltage to trigger a strike, enhancing safety.
By managing charge density, Tesla’s protector keeps the air non-conductive, preventing corona effects and streamers. As Tesla explained:
“My protector… secures a very low density and preserves the insulating qualities of the ambient medium, thereby minimizing leakage.” — Nikola Tesla, U.S. Patent No. 1,266,175
A large, rounded, ellipsoidal terminal like Tesla’s can dramatically increase safety, reducing the risk of lightning strikes and offering a more effective alternative to conventional lightning rods.
Preventive Lightning Protection Design by Tesla
Tesla’s vision extended beyond theory to practical design. In this 1918 drawing from the Electrical Experimenter, he illustrates a Victorian-style mansion protected by multiple lightning protectors, which aligns with standards like IEC 62305 that also advocate protection with multiple points. For enhanced safety, he advised using several units:
“For greater safety, it is advisable to employ a plurality of such protectors, suitably disposed.” — Nikola Tesla, U.S. Patent No. 1,266,175
Tesla’s 1918 drawing from the Electrical Experimenter, showing a Victorian mansion protected by multiple lightning protectors with rounded terminals.
Tesla also highlighted the importance of customization:
“The number of the protectors… should be determined by the expert in charge of the installation.” — Nikola Tesla, U.S. Patent No. 1,266,175
The number of protectors can thus be tailored based on the type of structure, surrounding environment, and local lightning density data, leaving flexibility to the expert overseeing the project.
From Tesla’s Vision to SPIN – A Modern Solution
For years, we delved into Tesla’s groundbreaking 1918 patent, analysing high voltage lab tests results, and rigorously tested lightning protection systems in the field—only to uncover a shocking gap: no true Tesla-inspired lightning protectors existed on the market! This preventive method could prevent countless accidents, slash strike probabilities, minimize risks and damages, and save significant costs—yet it was nowhere to be found.
Determined to bridge this gap, we took action and crafted SPIN: the ultimate Tesla lightning protector. Designed with precision to avoid sharp points or edges, SPIN prevents ionization and delivers unparalleled safety, bringing Tesla’s visionary design to life. Don’t settle for outdated solutions—discover the future of lightning protection with SPIN today!
Tesla’s 1918 lightning protector patent schematic, inspiring modern solutions like the SPIN by LPS Pacifica.
Dive Deeper: Discover Tesla’s Groundbreaking Lightning Protector Patent
Tesla’s 1918 patent (U.S. Patent No. 1,266,175) is arguably the most intelligent and reasoned scientific contribution to the field of lightning protection.
See for yourself and form your own opinion—read Tesla’s patent now.
Original schematic diagrams from Nikola Tesla’s 1918 patent, the foundation of our SPIN technology.