With anything in life, the most important factor is safety - and solar systems are no different.
The most common safety malfunction a solar system can experience is an arc fault. These often result in the destruction of an entire solar system and can spread to the house or building they are installed on.
Understanding arc faults is essential to preventing them, so here are the facts:
How do arc faults occur?
While air is commonly considered a non-conductive material, there are exceptions to the rule.
Picture the usual flow of electrical current passing through DC cabling, DC isolators or solar modules but instead being interrupted by a gap of air.
This high potential difference between conductors, or voltage, can often cause air molecules to breakdown into their ionised components, or Plasma. Depending on the temperature of the electrical arc, this can initiate the combustion of surrounding materials.
What causes an arc fault?
Typically a disruption in the conductor continuity or an issue in the insulation system is the root cause of arc faults. These can occur in 2 ways and are caused by a variety of factors. These include:
Conductor continuity can breakdown as a result of:
- Loose joints
- Joint corrosion
Insulation systems can breakdown as a result of:
- Insulation degradation or cracking due to UV exposure, aging and/or a flux in temperature
- Damage to the insulation caused during installation or later by future building works or rodents, birds, insects
- Water ingress to cables, conduits, the inverter, solar module, junction box or DC isolators due to poor installation and/or aging
How can you prevent arc fault in your system?
It's important to understand that in order for a system to arch, a continuous voltage is essential. Because AC voltage alternates continuously, varying between 0 and 100 volts per second, they often self-extinguish arches as their voltages alternate. DC systems, however, operate on a continuous voltage, creating the ideal environment for this to happen.
Choosing an AC system over a DC system drastically reduces the likelihood of an arching issue in a solar system - this information should be considered in the early stages of installing a solar system.
Microinverters are cleverly designed to convert DC voltage to AC at individual modules. These are an innovative way to ensure your system operates safely without needing to completely convert to an AC system.
If you choose to stay with a DC system, you can always add DC Optimisers to increase the safety of your existing setup. DC Optimisers work to control the DC voltage and power between the modules and the main string inverter.
What should I do if my system experiences an arc fault?
Switching off the inverter will not stop an arc fault.
In the event of an arc fault, dial 000 to contact emergency fire services to prevent the spread to the rest of your solar system and the building it is installed on.
Reach out to Excel Power to for more information or to organise repairs to your solar system in the event of an arc incident.