ABSTRACT Installations of photovoltaic systems connected or not to the electrical network have become increasingly popular, but it is often carried out by unqualified people using low quality components. The present study aims to describe the methodology adopted for the protection of grid connected photovoltaic systems (GCPVS) and the implications caused by their lack. Photovoltaic modules are typically installed in galvanized, painted, stainless aluminum or steel structures, which must be connected to a common ground, as these structures and any other components of the system could be energized by the photovoltaic array and may cause serious injuries or even death during routine maintenance, these fatalities can still result in ramifications for the entire industry, with millions of dollars in liability (for death or injury), negative publicity for GCPVS, and increased complications in obtaining licenses. Also, its components must be of good quality and the systems of protection must be well dimensioned and correctly installed, in order to avoid fire and electric damages, with reduction of possible damages in cases of short circuits.