This paper assesses the protection against electric shock in a photovoltaic generator (PVG), the dc side of a PV installation. Within this context, we discuss the applicability of the protection requirements of the International Electrotechnical Commission 60364, the international standard that provides guidelines for wiring in low-voltage (LV) electrical installations. The unique operational characteristics of a PVG, which differ from those of a conventional ac LV system, made it necessary to revise and adapt these requirements. With a view to discovering the effectiveness of electric shock protection in ungrounded PVGs, we carried out both a theoretical and practical study in a real PVG in order to analyze its electrical behavior. As part of our study, the feasibility of applying an "active" means of protection was experimentally tested in this same PVG.