The Solar Combiner Box 4-String is a DC combiner box that lands four PV strings in one enclosure. Across South Africa, solar installers, developers and businesses use it on larger rooftop and ground-mount arrays.
Each string gets its own fuse and surge arrester, with one DC isolator for the whole box. Every solar combiner box for sale should list its part ratings, and this one does.
Why Choose The Solar Combiner Box 4-String
One enclosure handles all four strings, so the inverter wall stays clear. As a PV array combiner box, it keeps every cable tidy at one landing point.
- Four string inputs and four protected outputs in one box.
- IP65 enclosure suits mounting near the array or inverter.
- Grouped wiring makes fault finding on site faster.
Voltage Ratings Inside This DC Combiner Box
The lowest-rated part sets the limit for the whole box. Here, the surge arresters and DC isolator both stop at 600V DC. Many listings skip this detail, yet it decides whether the box suits your strings.
Cold Morning Voc Check
Panel open-circuit voltage rises as the cells get colder. On a frosty Highveld morning, a string can sit well above its label voltage. Datasheets list this change as the Voc temperature coefficient.
Before you buy, add up each string’s Voc using the panel’s cold-weather temperature coefficient. That cold figure, not the label figure, must stay under the box’s limit. Strings that push past it need a different box.
Inverter And Array Compatibility
Its four outputs feed a string, grid-tied or hybrid inverter. Replace any blown fuse like for like with the Solar Fuse 15A 1000VDC. It sits in our Combiner Box Solar range, and it never suits AC circuits or battery cables.
Best Use Cases For Four Strings
- Installers expanding an array to four PV strings.
- Developers fitting a solar farm combiner box.
- Farms and off-grid sites with long cable runs.
This box suits installers rebuilding after a lightning strike, when unprotected strings left the inverter exposed. For businesses, it works as a string combiner box for solar when a new inverter adds MPPT inputs. Ground-mount fields benefit too, because one box keeps four long runs organised at the array.
Warranty Compliance And Trust
SANS 10142-1 and SANS 10142-1-2: PV DC wiring and embedded generation must follow the national wiring code. You need a Certificate of Compliance (CoC) from a registered electrician for the full PV installation.
The enclosure carries an IEC 60529 IP65 rating for outdoor mounting. Its DC isolator must be rated for DC PV switching, typically to IEC 60947-3. Confirm this on the data sheet before sign-off.
Earth the surge arresters with the Earth Spike M12 x 12mm 1.2m for proper protection. Proper earthing lets the arresters send a surge to ground, away from the inverter. Grid-tied or hybrid systems must be registered with the municipality or Eskom as SSEG.
Extra surge devices and DC breakers sit in our AC and DC protection devices range. Our solar installation team can fit the box and wire it to your inverter. Payment is by secure EFT or Visa card.
What Is Included
- Set of four 15A string fuses.
- 600V DC surge arresters, one per string.
- One 600V DC isolator.
- IP65 outdoor enclosure.
Delivery runs nationwide across South Africa in 2 to 5 working days. Order the Solar Combiner Box 4-String today and land four strings with every part rated.
Last Updated: October 2026
