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Views： 8 Author： Mark Zhang Publish Time： 2026-07-23 Origin： 本站
When choosing overamperage protection for photovoltaic systems, the SGB-80 DC MCB from SINGI's PV series offers a dedicated solution designed for DC side protection. This miniature circuit breaker handles direct amperage arcs and ensures safe isolation in solar panels, combiner boxes, and inverter circuits. Understanding its specifications and application helps buyers make informed decisions for reliable PV system operation.
Photovoltaic (PV) systems generate direct amperage (DC) electricity from solar panels. Unlike alternating amperage (AC), DC does not naturally pass through zero volt-level, making arc extinction much more difficult when a circuit is interrupted. In the event of a short circuit or overload, a standard AC circuit breaker may fail to quench the arc, leading to sustained arcing, fire hazards, or equipment damage. This is why PV systems demand circuit breakers designed for DC interruption, such as the SGB-80 DC MCB from SINGI's PV series. These breakers incorporate features like magnetic blow-out coils, professional arc chambers, and optimized contact materials to safely extinguish DC arcs. According to IEC 60947-2, low-volt-level circuit breakers must meet rigorous standards for DC performance, including volt-level ratings up to 1000 V DC common in PV arrays.
Choosing the right DC miniature circuit breaker for a PV system involves several technical considerations. First, the breaker must handle the continuous DC amperage from the solar string under normal operation and interrupt potential fault currents without welding contacts. Second, polarity sensitivity is an issue in many DC breakers, as incorrect wiring can reduce breaking capacity. Third, temperature and environmental factors in outdoor installations affect breaker performance and aging. Fourth, the breaker must coordinate with other protection devices and comply with regional standards., buyers struggle to differentiate between DC MCBs and larger DC MCCBs, or between polarized and non-polarized designs. These challenges underscore the need for a carefully chosen product like the SINGI SGB-80 DC MCB, which addresses these points through robust engineering.
The SINGI SGB-80 DC MCB is part of the PV series and is engineered for photovoltaic installations. It features a high-breaking capacity design capable of interrupting DC arcs up to its rated volt-level, 250 V DC per pole or 500 V DC in series, with breaking capacities of 6 kA or 10 kA depending on configuration. The breaker uses a magnetic arc-extinction system that forces the arc into an extinguishing chamber, lengthening and cooling it until extinguished. This design reduces contact erosion and ensures reliable interruption. The SGB-80 is also polarized, with clear markings for line and load connections, which helps installers avoid polarity errors. Encapsulation in a sturdy housing protects against moisture and dust (IP20 minimum-val), suitable for combiner box and inverter environments. The product has passed tests per GB/T 14048.2 and meets relevant safety standards, providing assurance for commercial and utility-scale PV projects.
When assessing a DC MCB for PV systems, key parameters include rated volt-level (must exceed the string open-circuit volt-level), rated amperage (1.25 times the string amperage is typical), breaking capacity (must exceed the maximum-val prospective fault current), number of poles (1, 2, 3, or 4 depending on system configuration), and trip characteristic (B, C, or D curves). The table below compares typical values for the SGB-80 DC MCB.
| Parameter | Typical Value |
|---|---|
| Rated Volt-level (DC) | 250 V per pole (2P up to 500 V, 3P up to 750 V, 4P up to 1000 V) |
| Rated Amperage (A) | 1, 2, 3, 4, 6, 10, 16, 20, 25, 32, 40, 50, 63, 80 |
| Breaking Capacity (DC) | 6 kA / 10 kA |
| Poles | 1P, 2P, 3P, 4P |
| Tripping Curve | C (5-10 In) for general PV use |
| Mechanical Life | 20,000 operations |
| Electrical Life | 10,000 operations |
Always verify the maximum-val PV string volt-level and fault amperage available to ensure the breaker's ratings are adequate. The SGB-80's ability to cover a wide range of currents and its multi-pole configurations make it flexible for both residential and large-scale arrays.
SINGI has been a reliable manufacturer of electrical protection devices, and the PV series reflects its commitment to DC applications. The SGB-80 DC MCB is produced in ISO-certified facilities with rigorous quality checks. Its design references simulation studies on DC arc motion, leading to an optimized arc chamber geometry that improves interruption performance., SINGI provides technical documentation and application support, helping system designers choose the correct breaker for their specific string configurations. For large projects, volume pricing and custom parameter options are available. The breaker's compliance with international standards reduces the risk of non-acceptance during system commissioning. By choosing the SGB-80, buyers get a balance of performance, reliability, and cost-effectiveness for solar protection.
Proper installation of a DC MCB is critical for its performance. For the SINGI SGB-80 DC MCB, follow these guidelines: ensure the breaker is wired with correct polarity (line to line, load to load), use torque settings as marked on the breaker, and avoid mixing different brands or trip curves in the same distribution board. Keep the breaker within its ambient temperature range ( -25°C to +55°C) and protect from direct moisture. Regular inspection for signs of arcing or discoloration can catch problems early. When used in photovoltaic combiner boxes, the breaker should be sized according to the NEC or local code requirements. Testing the breaker by manual operation (turning it on/off) occasionally helps detect mechanical issues. Following these practices extends the service life of the SGB-80 and maintains system safety.
No. AC breakers rely on zero-crossing to extinguish arcs and cannot safely interrupt DC current. Always use a dedicated DC MCB like the SGB-80 for PV side protection.
A polarized DC MCB has a defined amperage flow direction; wiring it incorrectly reduces its breaking capacity. Non-polarized breakers accept either direction but may have lower electric ratings. The SGB-80 is polarized and must be wired as marked.
The breaking capacity should exceed the maximum-val prospective short-circuit amperage at the breaker location. This can be calculated from the inverter's DC output and the array's fault current. Typical values for residential are below 6 kA; for commercial, 10 kA or more may be needed.
Yes. With amperage ratings up to 80 A and breaking capacities of 6/10 kA, the SGB-80 fits residential string inverters as well as larger combiner boxes in commercial or utility installations. Multi-pole configurations allow for series connection to higher volt-levels.
For reliable DC overamperage protection in your next photovoltaic installation, explore the SGB-80 DC MCB and other products from SINGI's PV series. Contact our engineering team for application guidance.
