For solar rooftop installations, it’s often unnecessary to install new AC earth pits. Existing AC earth pits, if designed properly to handle fault current, are usually sufficient.
In a solar setup, the overall AC current in the circuit doesn’t increase. Before solar, if 10A flowed in the AC circuit, the entire 10A came from the Grid. Now, with solar, 4A is supplied by solar and the remaining 6A is drawn from the Grid. Therefore, only 10A flows on the AC side overall. Since the current remains the same, existing AC earth pits can handle the fault current. Hence, there’s no need for new AC earth pits.
What’s a Fault current?
Fault current is the current flowing during a ground fault, where 0.1A may flow through a person into the ground. While various types of faults can occur, 98% are typically ground faults. In such cases, a line wire touching the cabinet can cause a ground fault, potentially shocking someone touching the cabinet.
A ground fault occurs when the current leaving a power source and the current returning through the neutral wire differ. For instance, while 6A may leave the power source, only 5.9A may return through the neutral line.
Overall, by ensuring existing infrastructure is properly designed, solar installations can operate safely and effectively without the need for additional AC earth pits.
