Download our 2025 Product Catalog for detailed drawings and technical parameters of all switchgear components.
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ZN85 series indoor vacuum circuit breakers are designed for 40.5kV metal-clad switchgear in three-phase AC 50Hz distribution networks. The interrupter and conductive parts are embedded in epoxy insulation to shorten creepage distance and improve dielectric strength. With compact upper–lower layout and spring operating mechanism, ZN85 is suitable for frequent switching in industrial plants, power stations and substations.
ZN85 series is an indoor high-voltage vacuum circuit breaker specially developed for 40.5kV metal-clad switchgear in three-phase AC 50Hz power systems. The three-phase vacuum interrupters and main conductive parts are arranged in a compact structure and embedded in epoxy insulation, which shortens the insulation distance, reduces the overall depth of the breaker and enhances dielectric performance under operating conditions.
The spring operating mechanism is installed within the circuit breaker frame and matched with the upper–lower layout of the primary circuit, resulting in smooth motion transmission and reliable mechanical behavior. This design makes the ZN85 suitable for frequent switching duty with long electrical and mechanical life while keeping routine maintenance requirements low.
Thanks to its compact outline, flexible operation and high breaking capacity, the ZN85 series is widely used in indoor switchgear cubicles as an incoming or outgoing feeder breaker, transformer protection breaker or bus sectionalizing breaker in industrial plants, power stations and substations.
For an overview of XBRELE’s complete outdoor and indoor VCB portfolio, please visit the Vacuum Circuit Breaker pillar page .
Select the model tab to view the corresponding technical parameters and outline & mounting dimensions for 40.5kV indoor switchgear design. (Current page shows ZN85-40.5; more variants can be added later.)
ZN85-40.5 is designed for three-phase AC 50Hz power systems with rated voltage of 40.5kV. The vacuum interrupter and main conductive circuit are embedded in an epoxy insulated structure, providing compact dimensions, high dielectric strength and reduced creepage distance.
With a spring operating mechanism and upper–lower layout of primary conductors, the breaker offers stable opening and closing performance, suitable for frequent operation in industrial plants, power stations and substations.
The following table is based on your ZN85-40.5 technical parameter sheet.
Main technical parameters — ZN85-40.5
Key electrical ratings for ZN85-40.5 indoor vacuum circuit breakers in 40.5kV switchgear applications.
| No. | Item | Unit | ZN85-40.5 |
|---|---|---|---|
| 1 | Rated voltage | kV | 40.5 |
| 2 | 1 min power-frequency withstand voltage (RMS) | kV | 95 |
| 3 | Lightning impulse withstand voltage (peak) | kV | 185 |
| 4 | Rated frequency | Hz | 50 |
| 5 | Rated current | A | 1250 / 1600 / 2000 |
| 6 | Rated short-time withstand current | kA | 25 / 31.5 |
| 7 | Rated peak withstand current | kA | 63 / 80 |
| 8 | Rated short-circuit duration | s | 4 |
| 9 | Rated short-circuit breaking current | kA | 25 / 31.5 |
| 10 | Rated short-circuit closing current (peak) | kA | 63 / 80 |
| 11 | Rated operating sequence | — | O – 0.3s – CO – 180s – CO |
| 12 | Breaking time | ms | < 80 |
| 13 | Rated short-circuit breaking current breaking times | times | 20 |
| 14 | Single capacitor bank breaking current | A | 630 |
| 15 | Back-to-back capacitor bank breaking current | A | 400 |
| 16 | Rated operating voltage (spring mechanism) | V | AC110, 220; DC110, 220 |
| 17 | Mechanical life | times | 10,000 |
Outline & mounting dimensions — ZN85-40.5
Typical outline and mounting dimensions for ZN85-40.5 installed in indoor 40.5kV metal-clad switchgear cubicles. Please confirm with the latest certified drawings for project-specific coordination.
| Item | Symbol | Value (mm) | Note |
|---|---|---|---|
| Overall height | H | — | Overall height of breaker assembly |
| Overall width | W | — | Including pole spacing |
| Overall depth | D | — | From front panel to rear connection |
| Fixed mounting hole spacing (horizontal) | L1 | — | Base horizontal bolt distance |
| Fixed mounting hole spacing (vertical) | L2 | — | Vertical spacing on base frame |
| Mounting hole diameter | Φ | — | Round or slotted hole size |
ZN85 indoor vacuum circuit breakers can be configured with protection relays, CTs/VTs and communication devices to form complete 40.5kV metal-clad switchgear solutions for industrial plants, power stations and utility substations.
Build a complete protection system around the ZN85 using project-specific relays and instrument transformers inside the switchgear cubicle.
ZN85 breakers interface smoothly with switchgear control and interlocking systems for safe local and remote operation.
When combined with bay control units or protection relays, ZN85 can be fully integrated into modern substation automation and SCADA systems.
Behind every ZN85 unit there is a controlled manufacturing flow – from epoxy embedded pole casting to routine testing – designed to ensure long-term reliability in 40.5kV metal-clad switchgear and substation applications.
XBRELE manufactures the vacuum interrupter pole assemblies, operating mechanism and switchgear interface parts in a coordinated process. Each step is monitored and recorded for traceability of every ZN85 breaker.
Vacuum interrupters are inspected for contact stroke, over-travel and resistance, then matched with moving and fixed conductors.
Primary parts are cast into epoxy under controlled vacuum and temperature, forming compact embedded poles with high dielectric strength.
The spring operating mechanism is assembled, lubricated and adjusted so opening/closing speeds, timing and bounce meet ZN85 limits.
Terminals, shutters, racking interfaces and auxiliary wiring are installed to match the specified metal-clad switchgear design.
Each breaker passes dielectric, mechanical and functional tests before packing and shipment, with results linked to its serial number.
Electrical routine tests verify the 40.5kV insulation level and switching performance of each breaker.
Routine-test reports can be supplied with the shipment on request.
FAT / QAP / ITP witness testing can be arranged for utility or EPC projects.
XBRELE supports panel builders, utilities and EPC contractors with predictable delivery, export-ready packing and engineering documentation for ZN85 indoor vacuum circuit breakers used in 40.5 kV metal-clad switchgear and substation bays.
Typical delivery times for ZN85 breakers depend on rating, quantity and required interface with the switchgear design.
ZN85 breakers are packed for safe transport and easy handling inside the switchgear factory or on the substation site.
XBRELE provides the technical files and support required for ZN85 integration into KYN, XGN and other metal-clad switchgear designs.
This section answers typical questions from panel builders, EPC contractors and utilities when selecting the ZN85 vacuum circuit breaker for 40.5 kV indoor metal-clad switchgear.