Residential Solar and Electric Vehicle Bonding and Grounding Methods for Galvanic Compatibility

Residential Photovoltaic (PV) panels are typically roof-top mounted and their accompanying DC/AC inverters are either collocated or installed inside the building. The PV panels and associated DC/AC inverter enclosures must be interconnected and grounded to a grounding-electrode according to NEC690.41-64. A small potential difference exists between the enclosure and its interconnection to the ground. The potential differences between a PV system enclosure and its ground wire, as well as, the potential differences between the inverter enclosure and its ground wire are at opposite polarities. Likewise, an Electric Vehicle (EV) controller enclosure and its ground interconnection, and a battery and its ground interconnection are also at opposite polarities. This observation can be generalized to any collocated generator and load DC power system. Therefore, the traditional galvanic compatibility rules can't be applied to generator and load enclosures because, if the interconnection potential difference and galvanic voltage polarities are opposite, then less corrosive damage occurs as oppose to same polarities a severe damage occurs. This article discusses galvanic compatibility issues of PV panels and EV groundings while providing a solution for this challenge using electrochemistry and electric circuit theory.