PDCE Lightning Rod FAQ

No power supply required. Only ground continuity is required.

It uses the electric charge generated on the ground. Induced by the negative charge at the base of the thundercloud, a positive charge builds up on the ground beneath the thundercloud. Lead it to the PDCE with a ground wire.

It is desirable that the ground resistance be as low as possible, but unlike electrical safety grounding, it does not have to be 10 ohms or less.

there is no need.
There are other companies' products that use salt to collect electric charges from the ground, but isn't replenishing the ground with salt every year an environmental burden? It's also very expensive. PDCE does not require supplementation such as salts.

PDCE is also a lightning rod, so it may be struck by lightning depending on the conditions. For example, when the height of thunderclouds is low due to thunderstorms in winter, PDCEs installed high in the air at high altitudes may be completely covered with thunderclouds. In this case, it will surely discharge to PDCE. Also, in other cases, if the electric field is very strong, a discharge between the PDCE, ie a lightning strike, can occur.

In that case, the effect of suppressing lightning strikes could not be demonstrated, but the minimum function as a normal lightning rod to guide lightning as a lightning rod was fulfilled.

Depending on the amount of lightning energy at that time, it may be destroyed. If lightning strikes near the top of the PDCE, it will discharge inside the PDCE and the current will flow directly to the ground. If a direct lightning strike to PDCE is expected (area), there is PDCE-Magnum with higher durability performance. The number of parts has been greatly reduced, and the high-voltage insulator technology used in high-voltage transmission lines has been incorporated to greatly improve durability.

If lightning strikes hit one by one in sequence, it's understandable to worry that the lightning that was avoided by PDCE will strike another lightning next. However, the preceding discharges occur simultaneously and occur in parallel from multiple locations in the thundercloud, branching out as they approach the ground. While approaching, most disappear before reaching the ground. Among these, the one that reaches the vicinity of the ground and receives the discharge from the ground becomes a lightning strike. A lightning strike will likely occur where the discharge from the ground is likely to occur, but it doesn’t know if it's the house next door. Lightning strikes are probabilistic.

PDCE only rejects the preceding discharges that reach near the ground and come above it, and at that point there may have already been several lightning strikes in distant places, but that is PDCE It has nothing to do with the extinguishing of the preceding discharge overhead. From a slightly more macroscopic point of view, the charge amount of the entire thundercloud is preserved if it is not struck by PDCE, so there is a possibility of other lightning strikes. It is constantly changing due to electrical discharges, lightning strikes, etc. In general, it takes about 20-40 minutes for a thundercloud to disappear, during which energy is consumed while moving.

For the above reasons, it is not possible to prove that avoiding lightning strikes with the PDCE will result in lightning strikes immediately outside the protection range of the PDCE. However, in the examples so far, we have never had any trouble with neighbors due to the installation of PDCE.

What can be said by matching the results in the laboratory, the installation results, and the lightning strike information is that there is a fairly high probability of protection if the horizontal distance is about 5 times the height of the PDCE and within a range of 100m.

In Japan, give priority to the protected angle or the protected area by the rotating sphere method. Regarding the scope of protection, the Building Standards Act has the highest priority. The extent of protection provided by PDCE has no legal meaning. Please treat it as an expected value as a mere plus alpha.

The same is true for lightning strike deterrence. In areas where winter lightning occurs on the Sea of Japan side, thunderclouds are low in altitude, and lightning may strike the PDCE itself. I assumed the case and raised the durability. Senior is sufficient for summer lightning on the Pacific side, but Magnum is recommended for winter lightning countermeasures. The Magnum has a very robust structure that integrates stainless steel metal hemispheres with high-voltage insulator technology used in high-voltage transmission lines. The number of parts is also significantly less than Senior, reducing the number of damaged parts.

I'm not saying it's bad, but it's the fact that the times have changed. The lightning rods that are widely used today were invented by Benjamin Franklin about 260 years ago, about 100 years before Edison was born and about 130 years before electricity became practical. At that time, it was the era of oil lamps, so it was safer to direct lightning to a lightning rod rather than hitting a random location. Since then, 260 years later, we are now in the age of networks for both electricity and information, and it is not uncommon for office buildings to have cables over 100km in length. Inducing lightning strikes creates a voltage in those cables that often destroys the electronic devices to which they are connected, a side effect of traditional methods of inducing lightning strikes into lightning rods. That's what it means.

Also, the thunder is capricious, and it is a fact that it does not always hit the lightning rod, but often hits near it. In August 2012, lightning struck an urban park in Osaka, Japan. There were tall buildings in the surrounding area, and there were tall trees in the park, but lightning struck trees that were not that tall. Even if there is a lightning rod, it cannot be 100% guided there. If the original purpose of guiding the lightning safely and letting the lightning current escape to the ground cannot be fulfilled, shouldn't we aim to prevent it from falling into the area that should be protected instead of actively guiding it? Even if the area cannot be protected and lightning strikes the PDCE lightning rod, the lightning current can be safely sent to the ground because of the reliable grounding work.

Although the lightning rod was able to induce lightning strikes, the following accidents occurred due to the large current (average about 30,000 amperes) flowing there.

A lightning rod attached to a lighting tower was struck by lightning, damaging the lighting control module.
[Shizuoka prefecture certain ground in Japan]

A lightning rod attached to the three-storied tower was struck by lightning, and a fire broke out from the fire alarm attached inside.
[Gifu Prefecture Important Cultural Property in Japan]

The lightning rod of the radio tower was struck by lightning, causing the ground potential to rise and destroy home appliances in nearby houses.
[Ishikawa Prefecture, Japan]

A lightning strike on a ship damages the radar, gyrocompass, etc.
[Certain shipping company]

If you are not using any electrical products, there is no problem even if a large current flows. However, modern life has so many devices that it would be impossible to live without them. To prevent these accidents, it is necessary to prevent large currents from flowing.

A normal lightning rod, a pointed rod, but it also disappears from the pointed end each time it is struck by lightning. It becomes just a stick while receiving lightning strikes many times. The installation of lightning rods is not the end of the line; annual inspections are also required. No lightning rod is permanently invulnerable to the natural world.

We often receive the question, "Is PDCE unbreakable?" Unfortunately it can break. This is a natural physical phenomenon, but in winter lightning, for example, the height of the clouds is low, so the PDCE lightning rod itself may enter the bottom of the clouds in high-altitude mountainous areas. Then, naturally, there is a discharge through the PDCE. Natural phenomena do not necessarily occur in the way that we assume, and the weakest point of the product is exploited. It is possible that the insulation part of the PDCE will be destroyed. This is because there are unique lightning strikes in Japan that cannot occur in the European countries that developed PDCE. This imported PDCE has broken several times in the past.

However, even if it breaks, the entire 360-degree circumference will not break, and since it is a part of it, the top and bottom electrodes will not break apart. Also, in terms of phenomena, even if it appears in the form of destruction of PDCE, it does not mean that PDCE alone is the cause. A detailed investigation is required to determine the cause, such as whether there was sufficient grounding. However, the probability of such damage is very low, so if it is damaged by a direct lightning strike, we will replace the PDCE free of charge.

However, since it is used in high places, it is true that even if it is partially damaged, it is not in good condition. We also improved the bonding method of the upper and lower electrodes by making a structure that does not generate discharge on the side of the PDCE . In a strength test, it was confirmed that the upper and lower electrodes would not separate even after a tensile test with a force of 10 tons.

In addition to our product, there is another product that protects against lightning strikes. The product collects a large amount of electrical charges from the ground and releases them into the air, creating a cloud of positive ions between the unprotected object and the thundercloud, which protects the unprotected object. There is some debate about this product as to whether the positive ions will stay above the protected object in the elements. Our products only charge the PDCE with positive charges collected from the ground, and do not emit ions that cover and wrap large objects such as unprotected objects, so they are not affected by rain and wind.

If snow piles up and covers the upper and lower electrodes, the upper and lower electrodes become electrically conductive, and the effect of separating them with an insulator disappears, resulting in a spherical structure. Although the original effect of PDCE is reduced, it still functions as a normal lightning rod, and it has been confirmed that lightning strikes are difficult due to its shape. Although it depends on the location, the winter thunderstorms tend to decrease from November to January, when there is a lot of dry snow, and in February and March when there is a lot of wet snow that wraps around the PDCE.

No consumables required.
Perform a visual inspection once a year and measure the ground resistance once every few years.

According to the results of observations by Dr. Koichiro Michimoto of the Japanese Government’s National Defense Academy, it has been clarified that the relationship between the altitude at which the air temperature drops to minus 10 degrees Celsius and the surface temperature is important.

1) When the zenith of the thundercloud is minus 20 degrees, minus 10 degrees and the altitude is 1800m or more, strong lightning is always observed.
2) When the zenith of the thundercloud is -20 degrees and the altitude is -10 degrees or less than 1800m, it becomes a single lightning or no lightning.
3) When the zenith of the thundercloud is hotter than minus 20 degrees, lightning does not occur regardless of minus 10 degrees altitude.
4) Minus 10 degrees When the altitude is 1800m or more and the surface temperature is 3 degrees or more, there is always a strong lightning strike.

An altitude of minus 10 degrees affects lightning strikes in winter, but most of them are less than 3000m in winter and less than 1000m in severe winter. It has been observed that winter thunderclouds are at lower altitudes than summer thunderclouds.

There are more round lightning rods than PDCE. It is called an ESE lightning rod. This is an abbreviation for Early Streamer Emission, and its principle is that if a sphere with a large surface area is lifted up into the sky, and since the surface area is large, an electric charge is accumulated there, the streamer will be emitted faster than lifting the electric charge from the ground ( It is called early (Emission). As a result, it is a normal type "dropping" lightning rod aimed at improving the capture rate of lightning strikes. The shape from a distance is similar to a sphere, but the principle is completely different. In terms of ESE, PDCE is NSE (Non-Streamer Emission), which prevents lightning strikes by not emitting streamers.

There is a radar reflector as an object that has a shape opposite to that of PDCE. It is attached to the mast of a small ship and consists of a flat reflector to return the received radar radio wave to its original direction. The PDCE lightning rod consists of two smooth hemispherical electrodes that have been tested for electromagnetic effects to obtain the European CE marking and comply with the EMC Directive 2004/108/EC.

Of course. Tables 2 and 5 of the JIS standard list three types of materials: iron, copper, and aluminum. Table 4 shows "hot-dip galvanized steel", "stainless steel", etc., as well as materials with mechanical, electrical and chemical (corrosion) properties equivalent to these materials (e.g. titanium). You can use it. PDCE lightning rods are made of those materials that sufficiently meet the specified thickness. The explanation of the JIS standard is explained in detail in "Lightning protection Q&A for buildings, etc. JIS A 4201:2003 correspondence" issued by the Institute of Electrical Installation Engineers of Japan (OHMSHA).

Disadvantages;
1) There are heavy 8Kg to 10kg.
2) The side area is also larger than that of a simple bar, so it receives a lot of wind pressure.
3) From (1) and (2) above, the support tube becomes thicker and heavier.
4) price is not cheap

To cover the disadvantage of Advantages include:
1) Since it is not affected by lightning strikes, large currents do not flow, and there are no side effects on the incidental facilities of the building.
2) Even if it cannot be suppressed, it is the same as a conventional lightning rod in terms of safely flowing the lightning current into the ground.
3) The perception of the world is changing, and it is not only enough to protect our own equipment, but also to prevent side effects on the neighborhood, and managers of outdoor facilities such as outdoor events, amusement parks, golf courses, schools, and parks. / Operators are becoming an era where it is necessary to measure the protection and safety of facility users.

It is proof that there is no trouble due to lightning strikes at your facility, but to show it objectively, it is easy to install a lightning strike counter that measures the number of lightning strikes in the lightning protection grounding terminal box installed in the PDCE's down-grounding wire. Effectiveness can be confirmed. We recommend a product with a lightning strike counter installed in the lightning protection grounding terminal box (product name: manufactured by LiC Geoenvironment Tech Co., Ltd.).