How It Works
How Lightning Protection Actually Works
No jargon, no sales pitch — just what the equipment does, why it looks the way it does, and what has to be true for it to protect your home.
The air terminal
What the Preventor Does
The Preventor is a mast-mounted air terminal that transmits ions into the atmosphere. It is designed to act in the moments before a direct strike: it creates a stream of charged ions that carries ground charges upward and reduces the electrical tension while a storm cloud is overhead, which can be enough to stop a discharge from triggering at all.
It cannot neutralize a cloud, and it does not claim to. What it does is lower the tension for the short time the cloud is passing — and when that is not enough to prevent a strike, it provides a conductive ion streamer that carries the discharge safely down to the grounding system instead of through your roof.
Because it is dynamic rather than passive, one properly installed system to HBP-21 Level II standards can protect a typical structure of 337,810 square feet. That is why your roof needs one terminal and two penetrations rather than a grid of rods and a network of cable.
History
Why It No Longer Looks Like a Lightning Rod
Lightning protection dates to the 1700s, and much of what is sold today is still essentially 1800s technology — small rods connected by a maze of exposed wire. Here is how the equipment actually evolved.
- 1749
The Franklin Rod
Benjamin Franklin's "experiment of procuring lightning from the clouds by a pointed rod" produced the first lightning protection: a rod to attract a strike and carry the charge to ground. Its coverage was limited — a cone beneath the rod — and today it is considered suitable mainly for church spires, industrial chimneys, and towers.
- 1836
The Faraday Cage
Michael Faraday's mesh enclosure was the first real update. Multiple rods at every salient roof point, bonded together with roof conductors and many down conductors, forming a cage. It works, but it leaves the centre of a roof unprotected unless more terminals are added, it is costly, and it requires a great deal of equipment and many roof penetrations.
- 1931
The Ionizing Conductor
Building on J.B. Szillard's experiments in France, Gustav Capart patented a device that ionizes the air around the terminal — an active conductor rather than a passive rod. This is the idea the modern system is built on.
- 1953
The Preventor
Gustav's son Alphonse improved his father's device into what we now call the Preventor, later perfected by the Heary Brothers of Springville, New York — in business since 1895 and the oldest and largest manufacturer of lightning protection equipment in the world. It is dynamic where the older methods are static.
Compare
Faraday Cage vs the Preventor
The honest comparison, on the three things homeowners actually ask about. Both systems work — they differ in what they cost you, what they do to your roof, and who has to be careful up there afterwards.
Cost
Conventional Faraday cage
- Significantly more costly
- No product performance insurance included
Preventor ESE system
- Far less costly — a much better value
- Product performance guarantee insurance included
Aesthetics
Conventional Faraday cage
- Requires a multitude of penetrations through the roof
- Requires numerous down leads to ground
- Requires a network of cable across the roof
- Tends to disturb the architecture
Preventor ESE system
- Generally no more than two roof penetrations
- Generally no more than two down leads to ground
- Only three primary components, far less cable
- Blends with the architecture
Maintenance & Safety
Conventional Faraday cage
- Many sharp air terminals across the roof are a hazard to anyone with roof access
- Re-roofing can require replacing the entire system
Preventor ESE system
- Low maintenance, and easy to modify if you build an addition
- Safer for maintenance personnel and anyone else on the roof
Grounding
The Part Nobody Sees
Grounding is the foundation of the entire system. Everything above it depends on the earth below it being able to take the charge.
What grounding actually is
Grounding is an intentional connection to the earth that limits the voltage lightning or a line surge can introduce. The air terminal and surge devices control voltage; the down conductors and earthing system convey it and conduct it safely away along a known path of least resistance. Without a low-resistance earthing design, no system offers complete protection — which is why ours is built around a single earthing system of 10 ohms or less.
Why Florida makes it harder
Your Florida home is built on ground with a great deal of sand. Sand and quartz are good insulators, not good grounding material, and loose particles conduct even less well. Electrical resistivity is the most variable of all the geophysical properties of rock — values can range across ten orders of magnitude. That makes the installer's grounding experience matter more here than almost anywhere else in the country.
How we measure it
We run the Wenner four-point method using an AEMC Ground Tester Model 6470-B, and give you a Soil Resistivity Report detailing the ground resistance around your home. The design follows the measurement, rather than the other way round.
Surge protection
Three Shields, Because One Is Never Enough
No single surge protector can do the whole job. Ordinary fuses and circuit breakers cannot deal with lightning-induced transients at all, so protection is staged — each shield reducing what reaches the next.
Shield One
At the main electrical service
A high-energy surge protector that takes the external transients caused by lightning. It absorbs the most voltage of the three.
Shield Two
At distribution and sub panels
Handles the medium-level transients generated inside your home — most often by large equipment such as air conditioning cycling on and off.
Shield Three
At the point of use
Suppression at the equipment itself, so whatever survives the first two stages is reduced to a level your electronics can absorb.
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