It needs no exaggeration. Solar panel fires are one of the worst issues which can emerge from solar panel defects. Often the result of previous underlying issues, one must consider, what can be done to prevent such extreme scenarios from occurring even if internal system defects arise?

There is one thing you can do which you’ll discover within 2 minutes of reading and it has more advantages than the prevention of solar panel fires alone. So much so this one thing will assist in the overall performance of the entire solar energy system. Ensuring you the opportunity to use more electricity from your solar system and less electricity is from the grid.

Fire - Solar Review

 Fact: 

DC optimised systems and micro-inverters have risen in popularity within the last decade from a growing concern amongst end-users towards the prevention of solar panel fires caused by DC arc faults.

Causes.

Fire - Solar Review

Unless alternative environmental factors are at play, solar panel fires are caused by one thing, DC arc faults. Dc arc faults are quite simply electrical energy flowing through an air gap which in turn creates an electrical arc. Combine the DC arc with a combustable material and fire is the result. It’s worth understanding the 3 main types of DC arc fault, as such knowledge ensures prevention. 

Series DC Arc Fault.

Series DC arc fault may potentially by the most common occurrence. It is simply a broken connection in the series (wiring) chain while the system is producing current. Often in the form of an inferior connection within the DC circuit. These poor quality connections can occur in more places than under the solar panels alone. One must consider the alternative vulnerable areas such as connections at the inverter, connections within DC isolators and any of the DC cabling or termination point within the string circuit.

Parallel DC Arc Fault

Parallel DC arc faults result from a breakdown in the insulation system causing current to flow between positive and negative. Two alternate polar conductors in the same DC circuit are often run close to each other. The insulation between the two wires can be damaged by multiple causes: UV breakdown, animals chewing on them, cracking, moisture penetration and mechanical damage. 

Ground DC Arc Fault

Ground DC arc fault arises from the failure of either positive or negative cable within the DC circuit to a conductive earth. The fault could occur between the roof, solar module frame, solar array racking, or any other grounded surfaces.

Areas of failure to facilitate the above DC arc faults stem from two key failures. Conductor continuity and insulation breakdown. Both of which are presented in varied forms and most often beyond the obvious. 

Conductor continuity:

  • Loose joints as a result of poor installation.
  • Loose joints as a result of poor quality connections.
  • Corrosion of joints due to continuous use.

Insulation breakdown:

  • Damage to insulation during installation.
  • Degradation of insulation over time as a result of UV exposure.
  • Cracking of insulation over time as a result of temperature changes (hot-cold).
  • Insulation degradation caused by ageing.
  • Damage to insulation by rodents, insects, birds.
  • Insulation damage by future building works.
  • Water ingress to junction box or solar module.
  • Water ingress to cables, conduits.
  • Water ingress to DC isolators from poor installation.
  • Water ingress to the inverter.

Side Effects.

Fire - Solar Review

Side effects of solar panel fires are fairly self explanatory. Destruction. Complete solar array and potentially even building destruction. 

Replacement becomes the only cure.  One of the most heartbreaking defects which can arise from improper system selection which more often than not the final defining factor being system cost. Spending a little more for safety and peace-of-mind also increases performance and overall output (yield). Find out how in the Prevention section below.

Prevention.

Fire - Solar Review

Beyond the usual “select quality components” or “choose a reputable installer” response, to truly ensure the prevention of solar panel fires you need one thing. Module-level inverter technology. A revolution which has become increasingly popular within the last decade to help mitigate the risk associated with DC arc faults and further more solar panel fires. Such technologies are in the form of micro-inverters and certain DC optimised systems such as SolarEdge with a safe DC mode.

Here’s the best part. Both of the above module-level inverter technologies ensure better overall system performance through module level optimisation. If one panel becomes shaded, the remaining solar panels still perform at their optimum. Maybe over time one panel may render itself defective, unlike a string inverter system, no other solar panels performance will be affected. 

Take things to the next-level. Often included at no additional cost with module-level optimisation is key to greater asset management. Module-level monitoring. True system performance in refined detail. Through such, an end user can see exactly how any particular solar panel is performing against the pack both instantaneously and over time. 

The prevention in this case offers far more value than safety alone. Combining both heightened safety, greater asset management and increased overall yields, the question must be asked, why would not incorporate micro inverter or optimiser technology?

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