Solar Junction Boxes Information

Solar junction boxes are protective enclosures that house electrical components for combination, connection, and termination for photovoltaic systems. They are also referred to as PV junction boxes and module junction boxes. A junction box protects the electrical connections of the solar panel from environmental conditions. Wire leads connecting the panel to the string and bypass diodes are located inside the junction box. The leads make the panel easy to connect in the string during the system’s installation process.

Solar junction boxSpecifications

When selecting solar junction boxes it is important to consider the casings, which should have strong aging and UV light resistance to protect them in severe outdoor environments. Like many enclosures designed to withstand severe conditions, solar junction boxes are often rated with a two-digit number based on the (Ingress Protection) IP Code, IEC 60529. Common IP ratings include:

  • IP 54 is mostly protected from dust and cannot be damaged by light water originating from all directions.
  • IP 55 is mostly protected from dust and cannot be damaged by low pressure water jets.
  • IP 65 is completely protected from dust and cannot be damaged by low-pressure water jets (ie, from a 6.3 mm nozzle).
  • IP 67 is completely protected from dust and cannot be damaged by immersion in water up to 1 m deep.
  • IP 68 is completely protected from dust and cannot be damaged by immersion in water deeper than 1 m.

Cooling mode and volume of their inner cavity are additional important specifications. 

Image credit:

Elvis untot (Own work) / CC BY-SA 3.0