Grounding system

A grounding system creates a low-resistance connection between system equipment and/or a system conductor - called a neutral or grounded conductor - to the earth. A grounding system is not necessary for an electrical system to function, the electrical distribution systems in some countries lack any type of grounding and others have complex grounding systems with additional measurement devices to protect users. In offgrid installations, it is common for small-scale DC-only PV systems operating at below 50V to lack a grounding system as it would increase the cost substantially without providing significant benefit. As system size, voltage, and cost increase the benefits of a grounding system grow. The electrical code for every country will contain information about the requirements and appropriate equipment for that location.

The preferred grounding system for an offgrid system is called a TN-S system, which has a grounded conductor (neutral) and a seperate ground that is run with each circuit. A TN-S grounding system carries has two distinct purposes each of which carries unique benefits: system grounding and equipment grounding.

System grounding

A proper grounding system is provides means to dissipate excess static electricity created by friction or lightning. This creates helps to create a stable system voltage and protect system equipment from damage.

Equipment grounding

A proper grounding system enables the overcurrent protection devices in an electrical system to automatically identify and disconnect faults before they pose a risk to users. When a fault - failure of insulation, loose connection - occurs, a properly grounded system provides a path the current to return through the earth to the grounded conductor which should cause an overcurrent protection device to open (disconnect) the circuit.