Bangladesh has seen a rise in solar energy since 1996. This growth was sparked by modest solar home system units, which were supported by the public and certain private sectors. As energy prices climb, it is now a rapidly expanding energy source. People are installing solar projects for Commercial and Industrial (C&I) buildings on their rooftops because of the land shortage and also making effective use of the roofs to generate revenue.
When this sophisticated system (Solar system) is handled and installed incorrectly, fire hazards can occasionally result. The number of fires started by PV systems has not been recorded anywhere. However, PV systems can have electrical problems much like any other electrical installation, including arc faults, short circuits, ground faults, and reverse currents. Hot spots that could start a fire can develop as a result of system failures such as improper connections, ruptured modules, and cable insulation breakdowns. Additionally, some PV fires can result from improper system installation.
MORE DETAILS AND REASON ON CATCHING FIRE ON SOLAR PANELS:
Poorly designed Systems
Solar system design is a lot more complex than it appears. In most cases, we consider it just placing multiple solar panels side by side and then connecting them by wires through inverters. Sometimes we are so eager to get started building a project that we don’t make any proper system design and start installing a panel on the roofs. This can lead to big and very expensive mistakes and after a big accident like a fire hazard, it will be more difficult for anyone to get access to the system.
Improperly installed Electrical Equipment
Even having an excellent system design, the solar system can be at risk if the installation is not done properly. There are a few major areas that affect the system performance and increase the risks of fires hazards are discussed the below
Water ingress into DC isolators
DC isolator is the major component in the solar system at the DC side. However, rooftop DC isolators are more exposed to the environment; they are more prone to damage and deterioration. Improper installation of DC isolators must cause water ingress into them and so many cases, accumulation is a must. This causes a DC arc flash which can eventually lead to a fire.
Use of poor quality MC4 connectors
MC4 connector is a very important component in solar system while sending the DC charge to the solar inverter/s. an under rated MC4 connector will lead to leakage of DC charges and too much leakage charges ignite a fire.
Improper fixation of Conduit at the Terminal
The conduits on the rooftop are used to ensure extra cover of the cables between the two terminals. If the terminals are exposed to direct sun and rain, and the conduits are not fixed at the terminals, there is a very high chance of water ingress. Then a DC arc flash and consequence might be a fire hazard.
Screws not Sealed
Unsealed screws on rooftop solar elements can allow water to slowly seep in from the other side of the screw. If the seeping is consistent and water accumulation is higher, the consequence might be severe. Apart from water ingress, insects can also get into that is also unsafe.
Incorrect sized cable glands
Incorrect sized cable glands allow additional openings in the solar system. And the extra holes which are not plugged up correctly can allow water to slowly seep inside; or insects might get into the components.
Improper penetration of enclosures
Drilling holes in an enclosure without proper sized cable glands can lead to water seeping in.
Penetrations made anywhere other than the lower surface of the enclosure have an increased risk of allowing water to drip onto components or even accumulate in the enclosure.
Cabel termination is a crucial part in the electrical power system. Terminals and other connections are needed to be tightened to flow the current properly. When the connections are not tightened properly, heat can be generated at that point. This can melt the plastic around the cable and start a fire.
Poor quality DC cable
Using an AC cable for the DC part is very common in the solar system to reduce the cost. A flexible AC cable can perform better, but in the long run, it creates a lot of troubles resulting in lower power generation, damage to cable insulation, rusting inside of the cable strands and finally, the damaged cable may ignite fire hazards.
Damage to module
Damage to the module makes internal cracks that are not visible also called microcracks. Microcracks can be caused by smashed modules, people walking on the panels, improper transport, etc. Microcrack creates hotspots in the cell, and it can lead to fires.
Lightning poses significant risks of complete or partial destruction to the solar project. When lightning strikes a solar panel array, it causes an induced transient current within the system’s wire loops that lead to the failure of the insulation, panels, inverter, and communication equipment and lead to a big accident like a fire hazard.
Selecting a good Design Team
Do you buy a house designed and constructed by a ‘Mason’?
If your answer is ‘Yes’, there is no point to engage a good designer to design your solar system.
So, when it comes to designing something, it is more important to have a better understanding/knowledge of it rather than having working experience on it for so many projects. Finishing so many designs with inaccurate/poor knowledge cannot irradicate the risks anymore.
So, if you want to reduce your solar rooftop system’s risks in the long run a good design team selection is the prime and foremost part.
A design team will design, simulate, and analyze a solar system before handing over it to the implementation and sourcing department.
Choosing experienced solar PV installers
A good contractor or implementation team is very important to implement a solar project with minimum/less deviation or errors. We have to choose expert installers who have a workmanship warranty and required technical experience and professional certifications. Additional industry certificates also show they have a well-trained workforce. Whether our rooftop solar PV is a grid-connected system, a back-up generator system, or an isolated battery-storage system, it should be installed in accordance with current safety codes and standards (local and standard or as per the jurisdiction authority)
Selecting better quality products
The temptation to buy low-quality products is high because of the low price and it is the only benchmark to secure a project in Bangladesh. But such panels, inverters, cables, isolators, breakers, and other parts can malfunction, causing a fire, and leading to higher costs in the long run. So, only buying a quality product can avoid this issue.
On the contrary, a better-quality product can also make sure a generation guarantee of the project. Better solar product means it complies with the minimum technical requirements to be better rather than manufactured from any specific country or region, or any ranking.
Just sharing an important piece of information about solar panels is, there is a huge difference between ‘Class A’ and ‘Tier 1’ solar panels. When you select a solar panel, you must select a ‘Class A’ solar panel. ‘Class A’ solar panel means the panel does not have any manufacturing defect. A ‘Tier 1’ solar panel manufacturer may have ‘Class B’ or C solar panels also. Class A, B, C, or D are manufacturing defects. Class A solar panel costs higher than ‘Class B’ or ‘Class C’ or ‘Class D’. And energy generation is higher using ‘Class A’ than that of other classes. And heat generation is higher for other classes solar panels than ‘class A’. more heat means more loss and more risks of fire hazards.
Solar inverter carries not more than 10% of a solar large-scale rooftop project. But it plays the main role to invert the solar DC energy to AC. If the sizing of an inverter is wrong and installed in the wrong manner with no/poor protection, the energy generation will be affected, and recurrent costs will be higher for a solar project and also increase fire hazard in the long run.
MC4 connectors must be of the best quality as it is the crucial part of connecting solar panels in series to generate more DC voltage by completing a single string. Poor MC4 connector puts the system with a higher fire hazard risk.
A better quality solar DC cable is a must for getting a performed solar system in its entire life cycle. And it also eliminates all the fire hazards. On top of these, energy wastage will be lower due to the lower voltage drop of the cables.
A surge protection system is another important component for the solar system to avoid the surge from the PV system to the other components or from the electrical system to the PV system.
Inspection and Maintenance
PV systems should be inspected regularly by qualified professionals, who should look for potential damage from rodents and other pests, which could compromise the wiring or insulation. Also need to clean under and around the panel because fire can propagate faster if there are leaves and dirt under the modules.
Apart from all these recommendations, there are a few less important safety precautions that shall be practiced having a safer solar rooftop system. However, we have discussed the most important observations only.
All the photos are collected from internet.