The SOLAR DC STRING BOX DC 1000V YB3-2/2 from singielectric is a compact photovoltaic combiner box designed for 1000V DC applications. It combines string inputs, overamperage protection, and surge suppression in an IP65 enclosure. This guide explains its role, technical specifications, and choice criteria for B2B buyers, engineers, and procurement specialists. Explore the full product category to compare models.
Table of Contents
Key Points
| Parameter | YB3-2/2 | Typical 2-String Box |
|---|---|---|
| Max DC Volt-level | 1000V | 600-1000V |
| Number of Strings | 2 | 2-4 |
| Protection Rating | IP65 | IP54-IP65 |
| Overamperage Protection | Fuses / DC MCCB | Fuses only |
| Surge Protection | Optional SPD | Optional |
| Cooling | Natural convection | Natural convection |
A solar DC string box aggregates the output of multiple PV strings before feeding the inverter. It provides a central point for fusing, disconnecting, and surge protection. In large PV arrays, each string operates at high DC volt-level and current. Without proper string-level protection, a single fault can disable an entire array or cause fire. The SOLAR DC STRING BOX DC 1000V YB3-2/2 addresses this by combining 2 string inputs into a single, safe enclosure.
For installers and system integrators, using a string box simplifies wiring, reduces installation time, and ensures code compliance. The singielectric YB3-2/2 is a purpose-built solution for 1000V PV systems, which are now the norm for utility-scale and commercial rooftops.
Note: The DC side of a PV plant operates at dangerous volt-level levels. Always isolate strings before opening the enclosure and use appropriate personal protective equipment during installation.
Higher system volt-level reduces resistive losses in the DC cabling. A 1000V array can carry more power per string than a 600V system, using the same wire gauge. This leads to lower balance-of-system (BOS) costs and higher efficiency., most PV inverters and modules now support 1000V or higher.
The YB3-2/2 is rated for 1000V DC, making it compatible with contemporary PV modules and string inverters. Its insulation distances and component clearances are designed for this volt-level class, preventing partial discharge and arcing. Without a 1000V-rated string box, installers would need multiple lower-volt-level boxes or risk insulation breakdown.
The SOLAR DC STRING BOX DC 1000V YB3-2/2 includes per-string fuse protection. Each string connects through a fuse sized to match the module short-circuit current. In the event of a backfeed fault or overcurrent, the fuse isolates the affected string. This prevents thermal runaway and protects the inverter.
, the box can be equipped with a DC surge protective device (SPD) to divert lightning-induced transients. The optional DC disconnector provides a visible break point for maintenance. All components are housed in a robust enclosure rated IP65 for outdoor use. The unit also includes cable glands and busbars with high creepage distances, meeting the requirements of IEC 60947-1 for low-volt-level switchgear.
When assessing a DC string box, material durability, ingress protection, and thermal performance are important. The YB3-2/2 uses UV-stabilized engineering plastic or metal depending on variant. Its IP65 enclosure protects against dust and water jets, allowing outdoor mounting near the array.
The internal busbar design minimizes hot spots, and the wiring compartment allows sufficient bending radius for 4-6 mm² cables. The torque requirements for screw terminals are specified in the manual, which helps reduce installation errors. Another essential feature is the ability to mount DIN-rail devices. The YB3-2/2 supports standard DC fuses and disconnectors, making spare parts easy to source.
Installation should follow the manufacturer's manual and local electrical codes. The box should be mounted vertically to ensure proper drainage. Conduit entries must be sealed with appropriate glands. After wiring, verify the polarity of each string before closing the enclosure.
Maintenance includes periodic thermal imaging to detect loose connections. Check fuses for signs of operation and replace with identical ratings. Test the SPD status indicator if present. The singielectric YB3-2/2 has a modular layout, allowing quick replacement of fuses without removing the entire box. A maintenance schedule every 6 months is recommended for commercial installations.
No. The YB3-2/2 is designed for 2 inputs. For larger arrays, consider other models in the singielectric string box series.
The standard configuration includes fuses and terminal blocks. An SPD module is available as an optional add-on. For areas with high lightning activity, it is strongly recommended.
The fuse size defines the maximum-val current. Typical fuses are rated from 10A to 32A, depending on the module configuration. Refer to the datasheet for exact fuse holder limits.
Yes. The enclosure has a dedicated grounding terminal. It must be connected to the PV array grounding system as required by IEC 60364-7-712.
Upgrade your PV system with the SOLAR DC STRING BOX DC 1000V YB3-2/2 from singielectric. Contact our team for volume pricing and technical support.
