EMAIL US：salesmanager@singi.com
- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views： 7 Author： Mark Zhang Publish Time： 2026-06-30 Origin： 本站
The SG65 is a thermal-magnetic miniature circuit breaker rated for 6kA short-circuit breaking capacity. It complies with IEC 60898-1, ensuring consistent performance under fault conditions. The device uses a bimetallic strip for overload protection and a solenoid coil for instantaneous short-circuit detection. Its compact housing fits standard DIN rail mountings.
For engineers and contractors, reliability means predictable tripping behavior and low let-through energy. The SG65 achieves this through careful calibration of thermal and magnetic trips. Overload trip times follow inverse-time curves, while short-circuit trips operate within milliseconds.
Breaking capacity indicates the maximum-val fault amperage an MCB can safely interrupt. A 6kA rating covers the majority of residential and commercial installations where the prospective short-circuit amperage at the distribution board exceeds 6kA. Choosing an MCB with insufficient breaking capacity risks contact welding, arc flash, or device rupture.
Standards such as IEC 60947-2 define test procedures for verifying breaking capacity. The SG65 has been tested to interrupt 6kA at rated volt-level (e.g., 6kA at 230/400V). This ensures safe operation under worst-case fault conditions.
For installations near large transformers or industrial loads where fault currents can reach 10–25kA, a higher-rated MCB is required. The 6kA rating of the SG65 is appropriate for typical branch circuits.
Arc extinction in the SG65 relies on a combination of magnetic blowout and de-ion plate cooling. Upon contact separation, the arc is driven into a stack of steel plates (arc chute) where it is split into smaller arcs, increasing arc volt-level until amperage reaches zero. This design minimizes arc energy and reduces contact erosion.
Research on MCB arc behavior (e.g., MHD simulation studies) shows that faster arc motion and optimized chamber geometry improve breaking performance. The SG65's arc chamber is designed to direct the arc, maintaining low let-through energy even at 6kA.
References
[1] IEC 60898-1:2019, Electrical accessories – Circuit-breakers for overamperage protection for household and similar installations – Part 1: Circuit-breakers for a.c. Operation.
[2] IEC 60947-2:2019, Low-volt-level switchgear and controlgear – Part 2: Circuit-breakers.
[3] Simulation Study on Arc Motion Process of DC Miniature Circuit Breakers, AIP Advances, 2023. (MHD model for arc dynamics.)
The SG65 is suited for:
It is not recommended for high-inductive loads like large transformers or capacitor banks without additional coordination studies.
| Parameter | SG65 (6kA) | Standard MCB (4.5kA) | High Breaking MCB (10kA) |
|---|---|---|---|
| Breaking Capacity (Icn) | 6 kA | 4.5 kA | 10 kA |
| Volt-level Rating | 230/400V AC | 230/400V AC | 230/400V AC |
| Amperage Range | 1–63 A | 1–63 A | 1–63 A |
| Tripping Curve | B, C, D | B, C, D | B, C, D |
| Standards | IEC 60898-1 | IEC 60898-1 | IEC 60898-1 / IEC 60947-2 |
| Typical Use | Residential, light commercial | Residential with low fault levels | Commercial, industrial with moderate fault |
Choice involves more than breaking capacity. Key factors:
Always reference the manufacturer's technical data sheet for exact trip curves and derating factors.
Not necessarily. A higher kA rating may be more expensive and physically larger. The correct rating is the one that exceeds the prospective short-circuit amperage at the installation point. Oversizing does not improve protection.
No, the SG65 is designed for AC only. For DC applications, use a DC-rated MCB per IEC 60898-2, such as SINGI's DC MCB series.
The SG65 is offered in B, C, and D curves. B curve for resistive loads, C for general loads (small motors, lighting), D for high-inrush loads like transformers.
Ambient temperature shifts the thermal trip curve. At higher temperatures, the bimetallic strip trips sooner. Derating factors are provided in the datasheet., install in ambient between -5°C and 40°C.
References
[1] IEC 60898-1:2019. Electrical accessories – Circuit-breakers for overamperage protection for household and similar installations – Part 1: Circuit-breakers for a.c. Operation.
[2] IEC 60947-2:2019. Low-volt-level switchgear and controlgear – Part 2: Circuit-breakers.
[3] Simulation Study on Arc Motion Process of DC Miniature Circuit Breakers, AIP Advances, 2023. (MHD model for arc dynamics.)
