Overview
The ZW8-12(G) Outdoor High-Voltage Vacuum Circuit Breaker is engineered for 12kV, three-phase AC power systems operating at 50Hz. It is primarily deployed in rural distribution networks, urban grids, and small-scale power systems to reliably control and protect against load currents, overloads, and short-circuit faults.
Featuring an integrated metal-enclosed design, the three-phase vacuum interrupters are housed within a robust enclosure using SMC insulating materials, ensuring high phase-to-phase and phase-to-ground insulation strength. The ZW8-12G variant incorporates an isolating switch, functioning as a sectionalizer, and utilizes a CT23 spring-operated mechanism with both manual and electric operation options.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| Rated Voltage | 12 kV |
| Rated Current | 630 A |
| Rated Short-Circuit Breaking Current | 6.3 / 12.5 / 20 kA |
| Lightning Impulse Withstand Voltage | 75 kV (peak) |
| Power Frequency Withstand Voltage (1 min) | 42 kV |
| Mechanical Life | 10000 operations |
| Operating Sequence | Openâ0.3sâClose-Openâ180sâClose Open |
| Closing Voltage Options | 110 V, 220 V |
| Opening Voltage Options | 110 V, 220 V |
| Weight (with G) | 152 kg |
Model Designation
- Z: Vacuum circuit breaker
- W: Outdoor type
- 8: Design sequence number
- 12: Rated voltage (kV)
- G: With integrated isolating switch
- /630: Rated current (A)
- -â¡: Rated short-circuit breaking current (kA)
Construction
The ZW8-12(G) adopts a three-phase pillar-type dry design with fully sealed construction, providing excellent resistance to moisture and condensationâideal for hot and humid climates. Terminal markings follow standard conventions: primary terminals labeled P1/P2 and secondary terminals S1/S2 for built-in current transformers.
The device includes a built-in Potential Transformer (PT) with per-phase fuses and a zero-sequence current transformer for ground fault protection. Safety Warning: Always de-energize and verify isolation before maintenance; never operate the isolating switch under load.
Technical Parameters
Service Conditions
- Temperature: -40 degC to +40 degC
- Altitude: <=3000 m (insulation adjustments required above this)
- Pollution Level: Suitable for Grade V environments (including dust, smoke, salt mist)
- Wind Speed: <=34 m/s (equivalent to 700 Pa pressure)
- Vibration & Seismic: Negligible external vibration or seismic impact assumed
- Custom Environments: For non-standard conditions, consult manufacturer for tailored solutions
Technical Data
| Item | Unit | ZW8-12(G) /630-6.3kA |
ZW8-12.5kA /630-12.5kA |
ZW8-12(G) /630-20kA |
|---|---|---|---|---|
| Rated Voltage | kV | 12 | 12 | 12 |
| Rated Current | A | 630 | 630 | 630 |
| Rated Short-Circuit Breaking Current | kA | 6.3 | 12.5 | 20 |
| Rated Short-Circuit Making Current (Peak) | kA | 16 | 31.5 | 50 |
| Rated Peak Withstand Current | kA | 16 | 31.5 | 50 |
| Rated Short-Time Withstand Current | kA | 6.3 | 12.5 | 20 |
| Rated Insulation Level | Lightning Impulse Withstand Voltage (Peak) | 75 | 75 | 75 |
| 1min Power Frequency Withstand Voltage | 42 | 42 | 42 | |
| Rated Operating Sequence | Open:0.3s:Close-Open:180s:Close Open | Open:0.3s:Close-Open:180s:Close Open | Open:0.3s:Close-Open:180s:Close Open | |
| Mechanical Life | Operations | 10000 | 10000 | 10000 |
| Rated Short-Circuit Breaking Current Breaking Times | Times | 30 | 30 | 30 |
| Closing Voltage of Operating Mechanism | V | 110, 220 | 110, 220 | 110, 220 |
| Opening Voltage of Operating Mechanism | V | 110, 220 | 110, 220 | 110, 220 |
| Contact Distance | mm | 11 +/- 1 | 11 +/- 1 | 11 +/- 1 |
| Overtravel (Contact Spring Compression Length) | mm | 3 +/- 0.3 | 3 +/- 0.3 | 3 +/- 0.3 |
| Phase Discrepancy of Closing and Opening | ms | <=2 | <=2 | <=2 |
| Contact Closing Bounce Time | ms | <=2 | <=2 | <=2 |
| Average Closing Speed | m/s | 1.0 +/- 0.2 | 1.0 +/- 0.2 | 1.0 +/- 0.2 |
| Average Opening Speed | m/s | 0.7 +/- 0.15 | 0.7 +/- 0.15 | 0.7 +/- 0.15 |
| Opening Time at Maximum Operating Voltage | ms | 15:50 | 15:50 | 15:50 |
| Opening Time at Minimum Operating Voltage | ms | 30:60 | 30:60 | 30:60 |
| Closing Time | ms | 25:50 | 25:50 | 25:50 |
| Resistance of Each Phase Main Circuit | muOmega | <=120 (with G <= 200) | <=120 (with G <= 200) | <=120 (with G <= 200) |
| Permitted Cumulative Thickness of Contact Wear | mm | 3 | 3 | 3 |
| Weight | kg | 152 (with G180) | 152 (with G180) | 152 (with G180) |
| Phase Center Distance | mm | 175 +/- 1.5 | 175 +/- 1.5 | 175 +/- 1.5 |
Installation & Wiring
Installation Diagram
Main Components: 1. Contact Blade, 2. Contact Base, 3. Contact Blade Support, 4. Insulated Pull Rod, 5. Operating Handle, 6. Isolation Switch Support, 7. Circuit Breaker
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Phase Center Distance | 175 +/- 1.5 |
| Contact Distance | 11 +/- 1 |
| Overtravel | 3 +/- 0.3 |
Selection & FAQs
Selection Guide
- Confirm a 12kV, 50Hz system and select the 6.3kA, 12.5kA or 20kA breaking rating above the calculated maximum prospective short-circuit current.
- Verify the 630A continuous rating and the corresponding making, peak-withstand and short-time withstand values against feeder load and protection studies.
- Choose standard ZW8-12 or ZW8-12G with integrated isolating switch; never use the isolator to interrupt load current.
- Specify 110V or 220V opening and closing control voltage and confirm compatibility with the protection relay, remote-control scheme, CT, PT and zero-sequence functions.
- Check −40°C to +40°C temperature, Grade V pollution duty, structure strength, clearances, grounding and access for 152kg equipment before ordering.
Frequently Asked Questions
Q1: Can this vacuum circuit breaker operate in severe pollution environments?
Yes, it is suitable for Grade V pollution environments, including dust, smoke, and salt mist. Ensure ambient temperature remains between -40°C and +40°C. Contact us for specific site assessments.
Q2: Which short-circuit breaking capacity is required for heavy industrial grids?
The 20kA model is required for heavy industrial applications. It supports a 50kA peak making current. Confirm your grid’s maximum fault level with our engineering team.
Q3: How does high altitude affect the insulation performance of this breaker?
Standard models are rated for altitudes up to 3000 meters. For installations exceeding this limit, insulation adjustments are required. Submit your exact site altitude for factory verification.
Q4: What is the process for requesting custom environmental adaptations?
Tailored solutions are available for non-standard conditions. Standard units handle wind speeds up to 34 m/s. Submit your specific project parameters to our technical department.
Q5: Which models are available for standard 12kV procurement specifications?
All models feature a 630A rated current for 12kV systems. Choose between 6.3kA, 12.5kA, or 20kA breaking capacities. Verify exact load requirements during the bidding phase.
Q6: What applications are best suited for the ZW8-12(G) outdoor breaker?
This 12kV outdoor vacuum circuit breaker is ideal for industrial enterprises and substations. It provides reliable protection in severe Grade V pollution areas.
Q7: What is the maximum peak withstand current for the 12.5kA model?
The 12.5kA model supports a rated peak withstand current of 31.5kA. This matches the rated short-time withstand current. Request the full technical datasheet for comprehensive specifications.