One of the common questions solar companies will be asked by potential customers is, “what happens to my roof in the case of a fire?” A homeowner considering a residential solar installation will want to know that their home and family are safe.
A business owner will want to be sure that their customers, employees, and the assets associated with their building are also safe. A common myth is that the fire department won’t touch a roof with solar panels on it. While a solar roof has some different considerations than a roof without solar panels, there is no reason, with the technology available today, that we can’t feel safe while inside a home or business with solar panels or while working on a building with solar in an emergency situation. In addition to the technology now available, many local fire departments are now trained on the best practices when responding to an emergency on a solar powered building.
The process of installing residential or commercial solar panels first involves a thorough approval process.
At the center of this approval process will be the AHJ (authority having jurisdiction), which is usually the local building department. This will be the ultimate authority in interpreting building and electrical codes and standards. For safety in a solar installation, the AHJ will refer to the NEC 2014/2017 (National Electric Code), which will require standards for proper grounding and shutdown in order to keep citizens and firefighters safe. In the NEC 2017, there are now standards for the “rapid shutdown” of solar panels which requires that the DC voltage circuits not run more than 1 foot from the solar panel and to fall within a safe voltage range within 30 seconds of system shutdown. Solar modules on ideal conditions will typically have an output of 30-60V, and a residential or commercial solar installation can reach 600-1500V, which undampered, can pose a serious electrocution risk to emergency responders.
The primary concern for firefighters is this voltage that can come off of a solar panel even when the solar disconnect switches have been shut off. One of the first things firefighters will do when they come to a residential or commercial solar installation is to shut off the power on the ground. There will always be an AC/DC disconnect switch to shut the power off to the solar modules, but a solar panel can still produce a dangerous voltage and be an electrocution hazard as long as there is even just a glimmer of sunlight left in the sky.
A solar panel will inherently produce power due to the workings of the cells on the face of the panel.
Some early recommended solutions that have been tried have been to spray foam on the modules, or to cover them with an opaque covering. These attempted solutions are not always reliable as foam can slide off of a solar panel and have a covering material to carry around can be impractical.
Effective solutions in managing the solar panel’s voltage has finally been achieved through adapting module level technology through companies like SolarEdge. SolarEdge has a technology known as “SafeDC,” which is a feature designed to automatically shut down the DC current and voltage in the solar module (panel) to the strings. SafeDC mode’s module level shutdown occurs automatically when the electric grid is down or if the building is disconnected from the electric grid, when the inverter is turned off, and when the thermal sensors on the optimizer hits over 85 celsius. In this SafeDC mode, the maximum voltage per solar module equals 1V. Since the maximum string length in a SolarEdge system is 50 modules, the maximum voltage will be 50VDC, which is well below the risk level.
A secondary concern for firefighters and emergency responders has been the ability to navigate the roof in the event of a fire. The concern is that the solar panels will block access to being able to vent the roof with an ax due to the fact that their covering is often edge to edge on a roof. With the new rapid shutdown requirement, firefighters can have peace of mind that should they need to hack through a wire to vent a roof, they will be safe from electric shock. Some towns have ordinances that require a 3ft set back along a roof’s edge to provide access, while others have deemed that requirement unnecessary.
Green Power Energy installs residential solar and commercial solar. The inverter on all of Green Power Energy’s solar installation has been SolarEdge with SolarEdge Power Optimizers.
With Green Power Energy’s solar installations, a customer can have peace of mind to know that fire safety will be the last of their worries since their solar system comes with the innovative rapid shutdown SafeDC feature. This keeps the family home safe, the business secure, and the emergency responder safe and confident in the event of a fire on their property.
