Lightning arrester installation

Recently I build my new house near Maharagama town. While building this house I allocate space for my antennas and observation equipment. Before installing antennas, I decided to install a lightning rod into the house. The main reason to install a lightning rod is because of the height of the building. It nearly 48 feet (approximately 15m) high, and located in open space, because of those reasons there is a very high probability to hit lightning into my antennas and other equipment.

Installed lightning rod

At the time of this writing, in here in Sri Lanka mainly two types of lightning arrestor systems are in use. The first type is a conventional lightning rod. This type of lightning rod is very common in Sri Lanka and it made with copper rods. The second type is ESE (Early Streamer Emission) type lighting arrestor. This ESE type is now getting popular in here and I saw it in a couple of new buildings. As I noticed most of the lightning arrestor installation companies are now moving into this ESE type solutions.

After reviewing lighting rods in the market, I decided to move into the conventional light rod. The main reason to select conventional light rod is because of its cost. Based on my findings decent quality ESE type lightning arrester costs around LKR 70,000 - LKR 120,000. Again this price further varies with its effective range. The conventional lightning rod costs LKR 9000 only. Also, the effectiveness of ESE type is still in debate. By considering everything I decided to stick to the low-cost conventional method.

Components of the lightning rod.

The next important thing about lightning rod installation is a grounding technique. To find out suitable grounding technique I measure ground resistance using ground resistance tester. After calculating everything I decided to use 25mm × 2.5mm copper tape as my ground conductor and 600mm × 600mm copper plate as a ground terminator.

Copper-tape which we used as a ground conductor.

I bought everything mention in here from a local electric shop. Considering all the components, most expensive items in this system are copper tape and copper plate.

The most painful part of this job is to install a ground conductor in the wall. Due to higher gauge and weight of the copper tape, it took an entire day to install ground conductor.

Support structure which we installed to place ground conductor to the wall.

Another view of the support structure.

After ground conductor installation, the next important task is digging a hole to install ground terminator. The dimension of the opening which we dig is 1.5m × 1.5m and nearly 3m in depth. To ensure lower resistance we combine copper earth-rod into the copper plate and install it inside the hole. Before closing the opening we pour nearly 50 kg of Bentonite powder mixture into it. Bentonite powder is maintenance free, commonly available, ground enhancement material and in here it ensures reliable conductivity between ground and copper plate/tape.

Ground connection layout.

Copper-plate installation with Bentonite mixture.

To fix lighting arrestor I build a structure using metal plates and tubes. The CAD drawing of the structure is available here.

Ground conductor after the installation.

It took nearly 3 days to install this lightning rod and finally now it's in service.

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