Photovoltaic inverter installed on the ground

Modern grounded inverters and PV arrays are not isolated from the grounded output circuit of the inverter. In this scenario, the equipment grounding conductor (EGC) of the PV circuit can be connected to the grounding terminal of the inverter, which is eventually connected to the AC grounding system and electrode within the premises.

The inverter is connected to the single ground rod used for both AC and DC using the GEC. While the PV array and inverter is connected to the main grounding terminal in the main panel through he EGC. In this grounding method, a single copper ground rod is used for both AC system and DC solar panel system using combined DC GEC and AC EGC.

However, some contractors, who had been accustomed to grounding the system at the inverter, still prefer to install a grounding electrode conductor at that point. While this is permitted, per 690.47 (B), it is done only for grounding the PV equipment and not for grounding the PV system.

If the components were all individually grounded, this could lead to voltage potential differences. The AC output terminals of the inverter supply the Neutral to Ground connection, and no secondary grounding connections are permitted. See also: Connect A Solar Panel To An Inverter (Here's How)

A grounding wire of 6 AWG must be connected to the grounding terminal on the inverter and connected to a single-point grounding connection wire. If there is no suitable grounding connection point, then the grounding wire from the inverter must be connected to the negative terminal of the battery bank for off-grid systems.

As shown in the fig, separate grounding rods are used for individual systems e.g. AC side and DC side. The equipment grounding conductor (EGC) from the main panel and PV arrays are connected to the Ground terminal and Ground bus in the inverter.