Fire Safety in PV installations

Fire Safety in PV installations is a big topic right now and something that is at the top of our agenda to ensure that at Jonstar we are leading the way using all of the best technology and specialist risk assessments to ensure we design and deliver systems that provide value for money, huge savings on electric bills and peace of mind that the systems are safe.

In 2017 RC62 guidelines for fire safety in pv were developed by the RISC Authority in conjunction with the Micro Generation Certification Scheme (MCS), further to this Zurich also released a white paper on the design, installation and maintenance of solar pv systems in August 2023. This was just after the release of the latest RC62 document in February 2023. These are all guidelines released by important stakeholders in the PV industry; however, they aren’t the regulations that the industry must abide by below:

MIS3002 The Solar PV Standard (Installation)
IET Code of Practice for Grid-connected Solar Photovoltaic Systems (referred to within this document as the IET PV Code of Practice)
BS7671 IET Wiring Regulations Eighteenth Edition

At Jonstar we apply the regulations and advise on the guidelines to try and ensure that each installation has a well balanced approach between what’s feasible to achieve once the potential array, safety and cost have been assessed.

Typically, Jonstar install SolarEdge on sites due to the advanced fire safety features compared with standard string inverters. The system has optimisers protecting each panel on the roof and controlling the output. The system has rapid shutdown, so each string drops below 30 volts within 30 seconds by the optimisers throttling the output of each panel to 1 volt.

Rapid shutdown is activated by thermal detection of temperatures above 85 degrees at the optimisers on the roof, loss of power to the inverter (at any isolation point) and if an arc fault is detected. Monitoring of the system can be done remotely even down to panel level. Additionally, a Firefighter Gateway can be installed linked to the inverters and the fire alarm system via an interface for automatic or manual shutdown of the system in the event there is a fire. The Gateway displays the string voltages and the operational status of the system so that the fire service can clearly see if SafeDC has been activated. Because DC Isolation is achieved electronically on the roof via the optimisers there is also no requirement for rotary DC Isolators that contribute to the majority of Solar PV fires.