DC arc faults happen when DC current travels somewhere other than the intended conductor.
There are several different kinds of DC arc faults
- Series - These are the most common, and can be observed when you disconnect two modules that are under load. They can occur anywhere within a DC series circuit. Prime examples are connections inside a module, junction box connections, connections between modules, and especially in field made connections.
- Parallel - This kind of arc fault happens between 2 cables that may be having an insulation break down, and short to each other. This can be caused by a multitude of factors including tracker equipment, environmental damage, wire insulation damage, and any kind of moisture that may be able to enter the circuit.
- to Ground - This can be caused by many of the same issues as a parallel fault, but instead of shorting to the PV circuit, it shorts to ground. This may not cause a ground fault within the inverter depending on the severity, and the cause of the arc fault.