Grounding conductor check

A grounding conductor check confirms that the inverter's protective earth (PE or PGND) cable and ground terminal are properly attached and actually connected to earth. Use it when the inverter reports an abnormal grounding, electrical grounding fault or missing grounding connection alarm. These alarms point to a PE, PGND or neutral wire that is not connected or not correctly connected. It is also one step in clearing a low insulation resistance alarm. In that case, measure the impedance between the PV string and PE as well, and repair any short circuit you find. If the PV strings are grounded, also confirm that the inverter's output side is connected to an isolation transformer. Commissioning checklists ask you to confirm that the grounding conductor goes to a grounding busbar or foundation electrode and that its cross-section is adequate. On TN systems, they also ask you to measure for a conductive connection between neutral and ground. Before recommissioning SMA inverters after components or power assemblies have been installed, confirm that the internal grounding conductor is correctly connected and working. For preventive maintenance, check once a year that the ground terminal and ground cable are still secure. Connect ground cables before the AC, DC and communication cables. Put a protective coating on the PE terminal to stop corrosion, and bond multiple inverters to a common ground bar so they share the same potential.