When you're piecing together the solar balance-of-system (BOS), the combiner box is the point where panel strings meet your inverter and disconnect. Choose a box that's too simple and you may miss the protection you need; choose one that's overbuilt and you'll pay for features you don't use. We're comparing two practical options: a compact two-string DC disconnect and a fully protected 2-in-2-out PV combiner.
Quick verdict
If you just need a service disconnect for two positive lines, the 2-String DC1000V box is the straightforward pick. If you want a combiner with more complete protection, the 2-in-2-Out PV Combiner Box is the better fit.
Comparison at a glance
| Feature | Buycheapsolar 2-String DC1000V | 2-in-2-Out PV Combiner Box |
|---|---|---|
| Price | $24.99 | $125.82 |
| Voltage rating | DC1000V | DC500V |
| Inputs / outputs | 2 strings in, used as disconnect or combiner | 2 PV inputs, 2 outputs |
| Protection | 2 x 63A DC breakers | 20A MCB, 20A fuse, Type 2 SPD |
| Box dimensions | ~4" L x 2.5" W x 3" H | 11.73" L x 11.73" W x 5.51" H |
| Best for | Simple two-string disconnect duty | Protected PV array combining |
Where each product wins
- Buycheapsolar 2-String DC1000V: This box wins when you want a dedicated disconnect point without extra circuitry. It arrives with 63A breakers already installed and works as either a combiner (with wire nuts) or a simple DC disconnect.
- 2-in-2-Out PV Combiner Box: This box wins when you want more than a simple switch. It arrives with the protective components built in, so your array gets overvoltage and overcurrent coverage from one enclosure.
Product notes
Buycheapsolar 2-String Combiner/Disconnect
At $24.99, the Buycheapsolar 2-String DC1000V is the low-cost way to add a two-line DC disconnect to a small array. It includes two 63A DC1000V breakers pre-installed in a compact rainproof CPVC box with a gasketed clear door, so you can see the switch state without opening it. You can use it as a combiner by joining wires with wire nuts, or run the two positive string leads through it and use it purely as a disconnect. If you need a large enclosure with room for extra components, this isn't it; the 4-inch-wide body keeps the footprint small but makes for tight access. It's a simple, no-frills disconnecting point that covers the basics.
2-in-2-Out PV Combiner Box with 20A Protection
At $125.82, the 2-in-2-Out PV Combiner Box takes a different approach. It accepts two PV inputs and provides two outputs, and it arrives with a 20A DC500V miniature circuit breaker, a 20A fuse, and a Type 2 surge protective device, so each string is fused and the whole box gets overvoltage and overcurrent coverage. The larger 11.73-inch enclosure leaves space for the extra components and makes wiring easier than the compact two-string box. The tradeoff is the higher price and the 20A per-string limit, which means it's aimed at moderate-size panel strings rather than high-current arrays. If your array doesn't need that level of protection, the extra cost is hard to justify.
Final choice by use case
- For a simple, no-frills two-line disconnect at the lower price, choose the Buycheapsolar 2-String DC1000V.
- For a fully protected combiner, choose the 2-in-2-Out PV Combiner Box.
