A roof covered with solar panels, a clear sky, and a house without power. This scenario awaits every homeowner whose solar installation is connected to the public electricity grid. When a power line fails, the inverter — the device that converts solar energy into usable electricity — automatically stops production. This is not a faulty installation, but a behavior required by regulations. Even though the sun is shining, the panels remain silent. The wind forecast for October 7 and 8, with gusts of 40 to 47 km/h and rain, could cause the first autumn power outages. Many homeowners will discover on that day that their solar roof produces nothing, even though they had it installed to reduce their dependence on the grid. The inverter cuts production during a grid outage to prevent electric shock to personnel working on the lines. This automatic disconnection is required by regulations (NF EN 50549 standard), not a faulty installation. Only a battery connected to a backup inverter can keep the house powered during an outage. This shutdown is required by regulation, not a failure. All photovoltaic installations connected to the public grid must include a disconnection protection. According to the National Photovoltaic Resource Center (Hespul), it allows to "stop production to prevent an installation from injecting into the public grid" when it is disconnected. This eliminates the risk of electric shock for personnel working on the lines. It also prevents "islanding," which is a section of the grid that remains energized, powered by private roofs. The inverter disconnects automatically by monitoring the frequency and voltage of the incoming current. The trigger thresholds are determined by the distribution network manager, not the installer or the homeowner. Regarding standards, the pre-standard DIN VDE 0126-1-1 was referenced until 2024, with French variants named VFR2014 and VFR2019. The NF EN 50549 standard has been applicable since January 1, 2025, in versions -1 or -2, and it is mandatory for installations over 800 W. It constitutes the technical reference for the European grid code RfG. Micro-inverters, installed one per panel, follow the same safety rule. Self-consumption does not mean independence from the grid. The vocabulary plays a part in this responsibility. A self-consumption installation needs to detect the electrical grid to produce. Self-consuming electricity reduces what you purchase, but does not eliminate the line. The device purchased for independence is designed to turn off precisely when the grid is down. The irony is that this shutdown proves that the installation complies with what the regulation requires. As of June 30, 2026, the power of the French photovoltaic solar park reached 34.0 GW, of which 3.0 GW were connected in the first half of 2026, according to the data and statistical studies service (SDES) of the Ministry of Ecological Transition. A year earlier, the same publication showed 28.2 GW. The gross production reached 14.1 TWh in the second quarter of 2026, an 18% increase compared to the previous year. The pace is sustained, and each quarter adds roofs whose behavior in case of an outage is already written. Outside of self-consumption, this production represents 8.6% of the electricity consumption in Metropolitan France. The dashboard tracks the connected park, including installations connected to Enedis' grid without an injection agreement. Connected to the public grid, they are subject to the same disconnection requirement. What is needed for the house to stay powered? A battery alone is not enough. Only an installation equipped with a battery and an inverter capable of functioning as a backup, separated from the grid, can power the house during an outage. The battery stores energy. The backup inverter cuts the connection to the line, so the house operates on its own circuit. This configuration is chosen at the time of ordering and must be clearly stated in the quote. Before signing, or upon receiving the work, asking the installer one question avoids a surprise: can the inverter function as a backup, separated from the grid, and with which battery? Ask for the answer in writing, in the quote or technical sheet. Also check the standard mentioned on the inverter certificate: NF EN 50549-1 or -2 for installations over 800 W. In installations injecting up to 250 kVA on the grid, the disconnection protection can be integrated into the inverters. For a private individual, the device that cuts is often the inverter itself, the one that was paid for to produce.