Side Mounted Indoor Vacuum Circuit Breaker: SanGao's Modular Solution for 12kV Distribution Systems
Designed for three-phase AC 50Hz, 12kV indoor switchgear, the SanGao Side Mounted Indoor Vacuum Circuit Breaker combines fixed sealed pole technology, a rotary isolation switch and a modular operating mechanism — delivering compact structure, high reliability and maintenance-free operation over its service life.
1. What Is a Side Mounted Indoor Vacuum Circuit Breaker?
The SanGao Side Mounted Indoor Vacuum Circuit Breaker is a new-generation medium-voltage switch component independently developed by Zhejiang SanGao Electric Co., Ltd. It is suitable for indoor switchgear in three-phase AC 50Hz, 12kV power systems, serving as a control and protection unit for electrical facilities.
The main circuit of the breaker is arranged longitudinally and adopts an advanced spring-operated mechanism together with fixed sealed pole technology. The result is a compact structure, high reliability, long service life and safe, maintenance-free operation throughout its service life.
Because of the special advantages of vacuum circuit breakers, this product is particularly suitable for frequent operations that require a rated working current, or for places where short-circuit currents are broken multiple times.
2. Modular Structure: One Frame, Multiple Functions
The product adopts a modular design: a frame structure that integrates high-performance, miniaturized high-voltage electrical products into one compact unit, including:
1Isolation Switch
Rotary isolation switch with a visible break after opening, ensuring a clear and safe isolation point.
2Sealed Vacuum Circuit Breaker
Fixed sealed pole technology improves environmental adaptability and insulation reliability.
3Grounding Switch
Integrated grounding switch with reliable interlocking to ensure operator safety.
4Sensors
Integrated sensing elements for monitoring and control functions within the switchgear.
5Interlocking Mechanisms
Mandatory mechanical interlocks between isolation switch, circuit breaker and grounding switch.
6Operating Mechanism
Modular operating mechanism that can be independently replaced or maintained.
Compatible Cabinet Size
The compatible cabinet size is (500 × 1000 × 1800) mm, making the breaker suitable for compact indoor switchgear installations where space is at a premium.
3. Key Features of the SanGao Side Mounted Indoor VCB
- Fixed sealing pole technology — improves environmental adaptability and insulation reliability of the circuit breaker.
- Excellent electrical and mechanical performance — reliable and stable mechanism with long service life.
- Extended mechanical and electronic lifespan — making maintenance-free circuit breakers possible.
- Rotary isolation switch — with visible fracture after opening for a clear isolation point.
- Mandatory mechanical interlock — between the isolation switch, circuit breaker and grounding switch to prevent misoperation.
- Modular operating mechanism — can be independently replaced or maintained, with good interchangeability.
- Manual or AC/DC energy storage operation — achieving remote control capability.
- Reliable interlocking structure — between cabinet door and grounding switch to ensure operator safety.
4. Safety Interlocking: Protection Against Misoperation
Safety is engineered into every layer of the Side Mounted Indoor Vacuum Circuit Breaker. Two key interlocking systems work together to protect operators and equipment:
Mandatory Mechanical Interlock
There is a mandatory mechanical interlock between the isolation switch, circuit breaker and grounding switch. This prevents misoperation by ensuring that these components can only operate in a safe sequence — for example, the grounding switch cannot be closed while the circuit breaker is closed, and the isolation switch cannot be operated under load.
Cabinet Door & Grounding Switch Interlock
The cabinet door and grounding switch are designed with a reliable interlocking structure. This ensures that the cabinet door cannot be opened unless the grounding switch is in the closed position, and the grounding switch cannot be opened while the cabinet door is open — safeguarding operators during maintenance and inspection.
5. Technical Specifications at a Glance
| Item | Description |
|---|---|
| Product Type | Side Mounted Indoor Vacuum Circuit Breaker |
| Rated Voltage | 12kV (applicable in 3.6–12kV power systems) |
| Rated Frequency | 50Hz, three-phase AC |
| Installation | Indoor switchgear |
| Main Circuit Layout | Longitudinal arrangement |
| Operating Mechanism | Advanced spring-operated mechanism; modular, independently replaceable |
| Pole Technology | Fixed sealed pole (embedded pole) |
| Isolation Switch | Rotary type, with visible fracture after opening |
| Interlocking | Mandatory mechanical interlock between isolation switch, circuit breaker and grounding switch; cabinet door and grounding switch interlock |
| Control Method | Manual operation or AC/DC energy storage; remote control capable |
| Compatible Cabinet Size | (500 × 1000 × 1800) mm |
| Service Life | Extended mechanical and electrical lifespan; maintenance-free within service life |
| Application | Residential communities, industrial and mining enterprises, power plants, substations |
6. Application Scenarios
The Side Mounted Indoor Vacuum Circuit Breaker is designed to serve as a control and protection unit across a wide range of medium-voltage distribution environments:
◆Residential Communities
Reliable distribution control for residential power supply systems.
◆Industrial & Mining Enterprises
Grid equipment and protection box control units for power design in industrial and mining applications.
◆Power Plants
Control and protection of electrical facilities within plant auxiliary systems.
◆Substations
Medium-voltage switching and protection in indoor substation environments.
◆Frequent Operation
Suitable for various types of loads and frequent operations requiring rated working current.
◆Repeated Short-Circuit Interruption
Designed for situations where short-circuit currents are disconnected multiple times.
7. Frequently Asked Questions
What is the difference between a side mounted and a standard indoor VCB?
The SanGao Side Mounted Indoor Vacuum Circuit Breaker features a longitudinally arranged main circuit and a side-mounted structure that integrates the isolation switch, circuit breaker, grounding switch, sensors, interlocking mechanisms and operating mechanism into a single modular frame. This makes it particularly suitable for compact indoor switchgear with a compatible cabinet size of (500 × 1000 × 1800) mm.
What is fixed sealed pole technology and why does it matter?
Fixed sealed pole technology embeds the vacuum interrupter and conductive components in solid insulation. This improves the environmental adaptability and insulation reliability of the circuit breaker, extends its mechanical and electrical lifespan, and makes maintenance-free operation possible during its service life.
Can the operating mechanism be replaced independently?
Yes. The circuit breaker adopts a modular operating mechanism that can be independently replaced or maintained. This provides good interchangeability and simplifies maintenance, reducing downtime.
Does the isolation switch provide a visible break?
Yes. The rotary isolation switch has a visible fracture after opening, providing a clear and verifiable isolation point for safe operation and maintenance.
How does the interlocking system protect operators?
There is a mandatory mechanical interlock between the isolation switch, circuit breaker and grounding switch to prevent misoperation. In addition, the cabinet door and grounding switch are designed with a reliable interlocking structure to ensure operator safety during maintenance.
Can it be controlled remotely?
Yes. The circuit breaker can be operated manually or through AC/DC energy storage, achieving remote control capability for integration into modern distribution automation systems.
Need a Selection Recommendation or Quote?
Tell us your system voltage, load type, operating frequency and switchgear dimensions. The SanGao technical team will recommend the most suitable Side Mounted Indoor Vacuum Circuit Breaker configuration for your project.
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Zhejiang SanGao Electric Co., Ltd.
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