How to deal with a PV system on Fire

Today while I was going through a social media website, I saw someone post pictures of solar thin film installations without proper gear for workers in India. This led me thinking about the safety measures to exercise when dealing with solar systems, especially when there is a fire breakout. Solar is gaining popularity with each passing day, and we are constantly hearing about new solar installations every day. These are surely exciting times for the world at large, since solar will go a long way in reducing pollution and global warming. However what is more important is that proper safeguarding measures must be taken to protect the well-being of the people.

So let’s talk about some safety measures that should be taken while working around PV systems. Generally these solar systems are very safe and reliable and hence are gaining traction even in our homes. However one must remember that these systems generate energy that has the power to transform into electricity and hence could be vulnerable in adverse situations.

Several solar panels are connected to form an array, which can have an output voltage of upto 100V. Installation and maintenance workers thus need to exercise caution while working with these systems. While string inverters can be shut down after the mains are cut, the DC voltage continue to stay as long as the sun is shining. This could put a fire-fighter at a life risk. As such many solar inverter makers like SolarEdge and Enphase Energy have now come up with safety switches, which enables the inverters to shut down automatically when required. Also when you switch off the power at the ground-based AC disconnect switch, the entire array is shut down. Microinverters and power optimizers can reduce such risks to a greater extent. Moreover SolarEdge’s Safety & Monitoring Interface are designed to monitor module level safety even for non SolarEdge inverters.

National Electric Code (or NEC) came up with a rapid shutdown clause in case of fire. According to the NEC 2014, PV systems must attain 30V or less within 10 seconds of shutdown initiation. Hence it is required to use equipments that are fire safe and can reduce risk to a certain level. Earlier in 2011 NEC also introduced Arc Fault Protection, where PV systems with 80 V or more output would be protected by a DC arc-fault circuit interrupter.

“As both a solar installer and firefighter, fire safety around PV systems is of particular interest to me.

The changes to the National Electric Code to address DC arc faults are an important step for those of us who deal with fires regularly.“ –Edmund J Haemmerle, Firefighter IAFF 3786, NJ Renewable Energy LLC.

Source: Enphase Handout PDF document (Safety is a hot issue in PV)

While these systems do work in place, with rapid changing technology new and new measures are being invented. The installers need to carefully choose their equipment keeping in mind the above points and safeguard precious lives and properties. Solar product will itself cause a fire is a myth, unless you fail to choose products with relevant product safety guidelines or are having improper connections. Don’t let it be the last thing to check before installing a rooftop solar!