ZW32 Vacuum Circuit Breaker Series
ZW32 series outdoor vacuum circuit breakers are widely used on 12kV and 40.5kV distribution networks. The unit integrates vacuum interrupter, solid-insulated embedded pole, operating mechanism and current transformer, offering reliable breaking performance for overhead lines, ring main systems and compact substations.
ZW32 vacuum circuit breaker with integrated pole & operating mechanism
ZW32 series is an outdoor high-voltage vacuum circuit breaker designed for overhead distribution networks. Each unit integrates the vacuum interrupter, solid-insulated embedded pole, operating mechanism and current transformer into a compact body, forming a fully enclosed structure suitable for long-term field operation.
The embedded pole design improves insulation performance and protects the interrupter from moisture, dust and environmental stress. Combined with a stable spring operating mechanism, the breaker provides dependable opening and closing under frequent switching conditions.
The series includes models for both 12kV and 40.5kV, allowing utilities and EPC contractors to deploy a unified breaker platform across different distribution voltage levels. Line-mounted installation reduces on-site work and shortens outage windows during upgrades or replacements.
For a broader look at XBRELE’s outdoor and indoor VCB ranges, please visit the Vacuum Circuit Breaker pillar page .
ZW32-12 & ZW32-40.5 — specifications and outline drawings
Select the voltage level below to view the corresponding product photo, key electrical ratings, and outline & mounting dimensions for engineering design and selection.
ZW32-12 technical overview
ZW32-12 is an outdoor vacuum circuit breaker for 12kV overhead distribution networks, typically used as feeder breaker, sectionalizing switch or tie switch on pole-mounted structures.
The breaker adopts a solid-insulated embedded pole and spring operating mechanism, providing reliable switching performance under frequent operations and harsh outdoor environments.
The table below lists the main electrical ratings for ZW32-12.
Key electrical ratings — ZW32-12
Values according to the ZW32-12 technical parameter sheet.
| No. | Item | Unit | ZW32-12 |
|---|---|---|---|
| 1 | Rated voltage | kV | 12 |
| 2 | Rated current | A | 630 / 1250 |
| 3 | Rated frequency | Hz | 50 |
| 4 | Power-frequency withstand voltage (1 min, dry-type, phase-to-phase / across break) | kV | 42 / 48 |
| 5 | Power-frequency withstand voltage (1 min, wet-type) | kV | 34 |
| 6 | Power-frequency withstand voltage (1 min, secondary circuit to ground) | kV | 2 |
| 7 | Lightning impulse withstand voltage (peak, phase-to-phase / across break) | kV | 75 / 85 |
| 8 | Rated short-circuit breaking current | kA | 20 / 25 |
| 9 | Rated short-circuit closing current (peak) | kA | 50 / 63 |
| 10 | Rated short-term withstand current | kA | 20 / 25 |
| 11 | Rated peak withstand current | kA | 50 / 63 |
| 12 | Rated short-circuit breaking current breaking times | operations | 30 |
| 13 | Rated short-circuit duration | s | 4 |
| 14 | Rated operating voltage / auxiliary circuit voltage | V | DC/AC110; AC/DC220 |
| 15 | Rated operating sequence | — | O – 0.3s – CO – 180s – CO |
| 16 | Over-current trip rated current | A | 5 |
| 17 | Mechanical life | operations | 10,000 |
| 18 | Cumulative allowable wear of dynamic & static contacts | mm | 3 |
| 19 | Rated current of overcurrent release | A | 5 |
| 20 | Current ratio of current transformer | A | 200/5; 400/5; 600/5 |
| 21 | Contact spacing | mm | 9 ± 1 |
| 22 | Contact overtravel | mm | 2.5 ± 0.5 |
| 23 | Average opening speed | m/s | 1.0 ± 0.2 |
| 24 | Average closing speed | m/s | 0.6 ± 0.2 |
| 25 | Opening time | ms | ≤ 50 |
| 26 | Closing time | ms | ≤ 100 |
| 27 | Closing bounce time | ms | ≤ 2 |
| 28 | Different periods of three-pole closing and opening | ms | ≤ 2 |
| 29 | DC resistance of each phase loop | µΩ | ≤ 80 (band isolation ≤ 150) |
Outline & mounting dimensions — ZW32-12
Outline and mounting dimensions for typical ZW32-12 pole-mounted installation.
| Item | Symbol | Value (mm) | Note |
|---|---|---|---|
| Overall height | H | — | Overall height of breaker assembly |
| Overall width | W | — | Including phase spacing |
| Mounting hole spacing (horizontal) | L1 | — | Base horizontal bolt distance |
| Mounting hole spacing (vertical) | L2 | — | To match cross-arm or steel structure |
| Mounting hole size | Φ | — | Oval or round hole diameter |
ZW32-40.5 technical overview
ZW32-40.5 is designed for medium-voltage overhead line power grids and 35–40.5kV substations, providing higher insulation level and breaking capacity based on the same embedded pole concept.
The breaker combines a solid-sealed pole with a reliable operating mechanism, offering long mechanical and electrical life with minimal maintenance.
The table below lists typical electrical ratings for 40.5kV ZW32 configurations.
Key electrical ratings — ZW32-40.5
Typical values for 40.5kV outdoor vacuum circuit breaker applications.
| No. | Item | Unit | ZW32-40.5 |
|---|---|---|---|
| 1 | Rated voltage | kV | 40.5 |
| 2 | Rated frequency | Hz | 50 / 60 |
| 3 | Rated current | A | 1250 / 1600 / 2000 / 2500 |
| 4 | Power-frequency withstand voltage (1 min, phase-to-phase / to earth) | kV | 95 |
| 5 | Lightning impulse withstand voltage (peak) | kV | 185 |
| 6 | Rated short-circuit breaking current | kA | 25 / 31.5 |
| 7 | Rated short-time withstand current (4s) | kA | 25 / 31.5 |
| 8 | Rated short-circuit making current (peak) | kA | 63 / 80 |
| 9 | Mechanical life | operations | 10,000 |
| 10 | Rated operating sequence | — | O – 0.3s – CO – 180s – CO |
Outline & mounting dimensions — ZW32-40.5
Outline and mounting dimensions for typical 40.5kV ZW32 installation.
| Item | Symbol | Value (mm) | Note |
|---|---|---|---|
| Overall height | H | — | Overall height of 40.5kV breaker |
| Overall width | W | — | Including phase spacing |
| Mounting hole spacing (horizontal) | L1 | — | Base horizontal bolt distance |
| Mounting hole spacing (vertical) | L2 | — | To match steel structure or frame |
| Mounting hole size | Φ | — | Oval or round hole diameter |
Protection, control and automation around the ZW32 series
ZW32 outdoor vacuum circuit breakers can be combined with protection relays, CTs/VTs and communication devices to form complete pole-mounted switching and automation solutions for distribution networks.
Protection & measuring combinations
Build a complete protection scheme around the ZW32 using your preferred relays and instrument transformers.
- Feeder over-current and earth-fault protection
- Directional / non-directional protection according to system design
- Integrated CTs for metering and protection functions
- Support for recloser curves and sectionalizing logic
Operating & control options
Flexible operating configurations to match manual, local and remote control requirements.
- Spring operating mechanism with motor charging
- Local/remote control selector with clear position indication
- AUX contacts for SCADA status feedback (open/close/ready)
- Compatible with pole-mounted control cabinets and RTUs
Distribution automation & communication
When combined with suitable controllers, ZW32 breakers can be used in automated distribution systems and smart grid projects.
- Support for common protocols via external IEDs (Modbus, IEC 60870-5-104, etc.)
- Remote open/close and status monitoring through SCADA
- Fault location, isolation and service restoration (FLISR) schemes
- Customized wiring and terminal arrangements on request
How XBRELE builds reliable ZW32 outdoor vacuum circuit breakers
Behind every ZW32 unit there is a controlled manufacturing flow – from embedded pole casting to routine testing – designed to ensure long-term reliability on harsh outdoor lines.
From embedded pole to finished breaker
XBRELE manufactures the vacuum interrupter pole assemblies, operating mechanism and housing in a coordinated process. Each step is monitored and recorded for traceability of every ZW32 unit.
- 01
Vacuum interrupter & pole assembly
Vacuum interrupters are checked for stroke, over-travel and resistance, then built into the solid pole.
- 02
Solid insulation casting & curing
Epoxy insulation is degassed, poured and cured to form a compact embedded pole resistant to tracking.
- 03
Mechanism integration & adjustment
The spring mechanism is assembled, lubricated and tuned so speeds, timing and bounce meet ZW32 limits.
- 04
Final assembly & sealing
Poles, CTs, terminals and enclosure parts are combined into a sealed outdoor body with anti-corrosion coating.
- 05
Routine testing & inspection
Each breaker passes electrical, mechanical and dielectric tests before packing and shipment.
Routine tests for every ZW32
Electrical routine tests verify insulation level and switching performance.
Insulation & switching verification
- Power-frequency withstand between phases and to earth
- Lightning impulse withstand on sample basis
- Contact resistance check for each main circuit
- Mechanical operating tests for O / CO sequences
Routine-test records can be supplied with the shipment if required.
Mechanical reliability
- Type-test verification of 10,000 mechanical operations
- Check of opening / closing speeds within limits
- Control of closing bounce time and pole synchronism
- Environmental checks for lubrication and low-temperature duty
Documentation & traceability
- Type-test reports and routine-test certificates
- Factory inspection records with serial number traceability
- Outline drawings & terminal diagrams in editable format
- Recommended maintenance guidelines for field crews
FAT / QAP / ITP witness testing can be arranged for utility or EPC projects.
Lead time, export packing and engineering support for ZW32 projects
XBRELE supports utilities, EPC contractors and distributors with predictable delivery, export-ready packing and engineering documentation for ZW32 outdoor vacuum circuit breakers at 12 kV and 40.5 kV.
Standard & project delivery
Typical delivery times for ZW32 breakers, depending on configuration and quantity.
- Standard 12 kV / 40.5 kV ZW32: about 15–25 days after order confirmation
- Projects with mixed ratings or accessories: usually 25–35 days
- Urgent orders can be discussed case-by-case according to production load
- Sample units available on request for type checking and approvals
Seaworthy packing & flexible shipment
ZW32 breakers are packed for long-distance sea or land transportation with proper protection.
- Individual breaker packed in export carton or wooden case with shock protection
- Moisture-protection and anti-rust treatment for outdoor installation parts
- Suitable for mixed containers with other XBRELE switchgear and transformers
- FOB Ningbo / Shanghai, CIF or other Incoterms can be supported according to the contract
Documentation & engineering assistance
XBRELE provides the documentation and technical support needed for network planning and project approval.
- Outline drawings, terminal diagrams and foundation details for ZW32
- Type-test reports, routine-test certificates and factory inspection records
- QAP / ITP preparation and FAT witness testing for utility & EPC projects
- Support with selection of ratings and configuration for specific overhead line schemes
Frequently asked questions about ZW32 outdoor vacuum circuit breakers
Below are some typical questions from utilities, EPC contractors and distributors when selecting XBRELE ZW32 vacuum circuit breakers for 12kV and 40.5kV overhead lines.