To safeguard human life as well as outdoor equipment from excessive contact voltages and lightning strikes, and to limit transferred potential to a minimum, an earthing system is required. To minimise the surge voltage and impact by providing low resistance in the earth grid or path. The goal of earthing design is to offer a path for lighting disconnection while also keeping the highest voltage gradient throughout the surface within safe limits during a fault or surge.
The earthing system comprises mostly of an earthing grid buried near protective equipment in the surface area. A collector network will run from the earthing network to every equipment that has to be earthed. Vertical risers/earthing stips/suitable size cable connect the entire collector network to the earthing grid at various elevations.
What exactly is lightning?
As we all know, lightning is a common occurrence, and everyone must have witnessed it during a rainy session. There are two charges in any voltage circuit. One is optimistic, while the other is pessimistic. Now, negative charges go in the direction of positive charges to complete the circuit with the help of a path such as a wire, conductor, or even air. As a result of dielectric breakdown in the air, negative electric charges build up in a thunderstorm and discharge to the ground (positive/ no charge) area.
Why is earthing necessary?
Earthing is utilised for safety and surge prevention against lightning and other types of surges. As a result of the voltage discharge, a large amount of current (about 20-150kA) flows during lightning. If a structure, light tower, human, or other outdoor equipment is struck by surge or direct lightning, a high voltage impulse is transferred to the ground, affecting the body and equipment.
What are the advantages of grounding?
Earthing is necessary for safety reasons, and the government recommends that earthing be used for any system protection. It is required for industrial purposes and is also suggested for domestic uses. The following are some of the key advantages of using an earthing system:
- To protect solar PV module/plates mounted outside from lightning.
- To avoid any human casualties as a result of the surge.
- For the protection and safety of expensive equipment, as well as to avoid any big losses.
- To comply with government regulations in order to obtain clearance for both industrial and domestic applications (above 50kW Solar plant system).
What is the process of earthing?
Due to a surge or lightning strike, a high voltage impulse is sent into the earth through the air and any other equipment connected to the earth, such as buildings, people, tower poles, and so on. We know that every material has some resistance, therefore we can divert the lightning course or minimise any hazards by creating a low-resistive surge channel to mitigate the lightning impact. For energy distich, charges always follow the least resistive path or the closest point. As a result, a lightning arrester is installed on top of any protective equipment and is connected to a separate earthing strip/cable that leads to the earthing pit, resulting in a low resistance strike path.
Beginner Guide for Earthing Installation
a. Earthing Kit Installation in Plain Areas
b. Earthing Kit Installation in Hilly Areas
For normal area as like house, ground area, pole etc. we can provide standard earthing with buried of copper/GI material 3 meter rod in to the ground with some soil enhancing compound material to achieve low resistive path for earthing and lightning.
Step 1: Check Requirement of LA
Survey Solar Panel Installation Area, if you find any maximum height buildings in 30 feet (10 meters) radius areas, there is no need of lighting arrester on that site. If your solar panel installation is on maximum height there, it must be install Lighting arrester.
Step 2: Measure Distance & Height of Installation
If you check step 1, then you should measure the distance from solar panels and lighting arrester installation. The standard guideline is distance should be 3-4 ft. from solar panels and lighting arrester. And the second step is height of lighting arrester should be 12 to 15 ft. from solar panel installation. It can be vary. If anyone installs solar panels on high rise panel stands, then it should be approx. 12 to 15 ft. The golden rule is 4 to 5 ft. maximum from solar panels.
- Distance: 5-10 ft. distance from solar panel installation
- Height: 6 to 7 ft. height of solar panel installation
Step 3: Use Insulator
Porceline insulator (suitable for 1.1kV) to avoid touching of earthing flat material with surface.
Step 4: Earthing Pit & Chemical Compound
Three (3) nos. Earthing pit recommended as per Govt. Guideline. One is for Panel Stand, Second is for Inverter & third is for Lighting Arrester. Some Soil enhancing chemical compound material (charcole & bentonite mixed clay)
Step 5: Wiring
16 sq. mm. flexible Cable for for LA earthing connection. You can put all incoming wires in single pvc pipe.
The price of an earthing kit
The cost of an earthing kit varies depending on the material chosen and the solar plant’s rating, however for a solar system with a capacity of up to 25 kW and a GI flat/riser rod earthing kit, the cost would be around Rs. 8000 per earthing kit. That means that if you install three earthing kits, the total cost of all rooftop solar plants will be around Rs. 25,000. All components, as well as installation, are included in this price.
There are numerous companies offering earthing solutions on the market. Earthing solutions and kits are available with a wide selection of earthing material alternatives at G8Solar. Please visit G8Solar or get in touch with our team of solar experts.