The Importance of Chemical Earthing in Solar Installations
A solar rooftop or ground-mounted array represents a substantial capital investment. Because solar installations are placed in elevated, open areas, they are highly vulnerable to environmental hazards such as lightning strikes, electrostatic build-up, and power surges. Without a robust pathway to dissipate these fault currents safely into the ground, a single surge can destroy expensive grid-tied inverters and damage PV panels. In extreme cases, it can pose a severe shock hazard to maintenance personnel.
What is Chemical Earthing?
Traditional earthing methods rely on a pipe or plate buried in a mixture of charcoal and common salt. While cost-effective initially, charcoal-salt systems suffer from several severe limitations: the salt dissolves over time with rain, the charcoal dries out in summer, and the rod is highly susceptible to rapid rust and corrosion. This causes ground resistance to spike, rendering the safety system useless.
Chemical Earthing resolves these issues by using a specialized Earth Enhancement Material (EEM), typically a bentonite-clay or carbon-based conductive compound, backfilled around a heavy-duty copper-bonded or hot-dip galvanized steel electrode. This chemical compound is highly hygroscopic (it retains moisture) and does not wash away, maintaining a low soil resistivity permanently without the need for periodic watering.
Key Components of a Solar Safety Earthing Loop
A complete solar system earthing network requires three distinct loops, which must not be short-circuited directly above ground:
- DC Earthing: Connects the metallic frames of all PV panels and the mounting structure (JSW rafters/purlins) to direct static charge and leak current into the ground.
- AC Earthing: Connects the metallic chassis of the inverter, AC distribution box (ACDB), and main switchgear to provide a fault clearing path for the utility grid.
- Lightning Protection System (LPS): Connects the Lightning Arrestor (LA) installed at the highest point of the structure directly to a dedicated grounding electrode. This pathway must be as straight as possible to prevent side-flashing.
Ground Resistance Targets
According to Indian Standard IS 3043 and IEEE guidelines, the ground resistance of the earthing system should ideally be less than 1 Ohm for industrial setups, and must not exceed 2 Ohms for commercial solar systems. Maintaining this low resistance ensures that fault currents take the path of least resistance through the grounding loop rather than through sensitive internal inverter circuits. Turvotek distributes premium, high-micron copper-bonded earthing electrodes and chemical backfill compounds that guarantee low resistance even in dry or rocky soil conditions.