When you have more than one string of solar panels feeding a single inverter, you need a combiner box to safely merge the positive and negative lines into one output. The two boxes here both include a 63A circuit breaker, but they differ in how many strings they accept, how they handle fusing, and what they cost.
Quick Verdict
If you need to combine six separate strings and prefer a lockable metal housing with IP65 weather protection, the 6 String Solar Combiner Box with 20A Fuse, Surge Protection & 63A Breaker is the more capable unit. If you have four strings or fewer and want a lighter, corrosion-resistant box that still includes surge protection and a lightning arrester, the Solar Combiner Box PV Combiner 63A Circuit Breaker 4 String For Solar Panel Kit is a practical lower-cost choice.
Comparison Table
| Feature | 6 String Solar Combiner Box | 4 String PV Combiner |
|---|---|---|
| Price | $197.99 | $62.54 |
| Number of strings | 6 | 4 |
| Fuse rating | 20A | 10A |
| Circuit breaker | 63A | 63A, 550V |
| Surge protection | Yes | Yes |
| Lightning arrester | - | Yes |
| Housing | Metal spray | ABS + PC |
| Weather rating | IP65 | - |
Where the 6-String Box Wins
The 6-string combiner box gives you more room to grow a larger array. Its 20A fuses allow each string to carry more current before protection trips. The metal spray housing with a lock and key is better suited for outdoor or semi-public locations where you don't want easy access to live terminals. The IP65 weather rating also makes it a safer bet for exposed rooftop or pole mounts.
Where the 4-String Box Wins
The 4-string box is the clear winner on price and simplicity. Its ABS and PC construction is impact- and corrosion-resistant while staying light enough for easy wall mounting. It also includes a high-voltage lightning arrester plus two surge protection devices, so it's not lacking in safety for a smaller system.
Product Notes
6 String Solar Combiner Box with 20A Fuse, Surge Protection & 63A Breaker
This box is the logical pick when your array consists of five or six separate panel strings. The included fuses give each string a higher overcurrent ceiling, which can be important if you're using larger panels or longer wire runs. It's pre-wired and has a built-in ground connector, so installation is straightforward. The metal spray housing with lock and key adds physical security, and the IP65 rating means it can handle rain and dust in most outdoor settings. The trade-off is the price: at $197.99, it's the pricier option here. If your system needs only four strings, that extra capacity isn't useful.
Solar Combiner Box PV Combiner 63A Circuit Breaker 4 String For Solar Panel Kit
The 4-string box is for builders who want functional protection at a lower initial cost. For $62.54, you get a high-voltage lightning arrester and two surge protection devices, plus a durable ABS and PC housing that resists impact, corrosion, and wear. It also uses natural cooling, so there are no fans or moving parts to fail. The limitation is the 10A fuse rating per string, meaning each string's current must stay below that level. If you plan to exceed that or add more than four strings, you'll quickly outgrow this unit.
Final Choice by Use Case
For a roof or ground array with five to six strings, go with the 6 String Solar Combiner Box because of its higher fuse capacity, lockable metal enclosure, and IP65 protection. For a smaller installation of up to four strings where budget is a priority, the 4 String PV Combiner delivers the required protection without the extra expense.
