The solar panel junction box is the output interface of the solar module. It wires the four solar connectors together.

Each solar junction box has two wires. One wire is the DC positive (+), and the other is the DC negative (-).

These can be connected to the solar PV panels either serially (series connection is when solar PV panels are wired together by connecting the positive lead on one PV panel to the negative lead on another PV panel to increase the voltage of the string).

The second is in parallel (Parallel wiring requires the positive leads to be connected and the negative leads to be connected).

The cables from a solar panel junction box transport the electricity from the solar PV module to the string. Modern PV solar panels tend to use the MC4 connectors because they make wiring the PV array much simpler and faster.

Besides, the PV junction box encapsulates solar bypass diodes that keep solar power flowing in one direction and prevent it from feeding back to the solar PV panels.