ZN63 (VS1)-12kV Indoor Vacuum Circuit Breaker 630-3150A 20-50kA | KYN28A-12 Switchgear IEC GB Thomas Electric

Product Overview

The ZN63 (VS1)-12 is a three-phase AC 50 Hz indoor high-voltage vacuum circuit breaker rated 12 kV, designed for protection and frequent switching in metal-clad switchgear such as KYN28A-12. Rated currents span 630 A to 3150 A with short-circuit breaking capacities from 20 kA to 50 kA, covering distribution, transformer and motor feeders in industrial plants, mining power networks and substations.

Product Display

ZN63 (VS1)-12kV Indoor High Voltage Vacuum Circuit Breaker - display

ZN63 (VS1)-12kV Indoor High Voltage Vacuum Circuit Breaker - poster_display

Model Designation

ZN63 (VS1)-12kV Indoor High Voltage Vacuum Circuit Breaker - model

Model format: ZN 63 − 12 / □ − □

Z — Vacuum circuit breaker
N — Indoor installation
63 — Design sequence number
12 — Rated voltage (kV)
First □ — Rated current (A)
Second □ — Rated short-circuit breaking current (kA)

Service Conditions

Ambient temperature: −10 °C to +40 °C (storage and transport permitted down to −30 °C)
Altitude: not exceeding 1000 m above sea level
Relative humidity: daily average ≤ 95%, monthly average ≤ 90%
Seismic intensity: not exceeding degree 8
Installation site free from fire, explosion risk, severe dust, chemical corrosion and intense vibration
Special service conditions: custom environmental adaptations available on request

Construction

The vacuum interrupter is housed in an APG cast insulating pole with reinforced ribs and skirt edges, which shields it from dust and moisture and provides maintenance-free, stable insulation in polluted indoor environments. The integrated VET spring-charged mechanism supports electric and manual operation, with linkage transmission and buffered damping that limit contact bounce and rebound over a 10,000-operation mechanical life.

Primary terminals are marked P1 (source side) and P2 (load side); secondary circuits provide S1/S2 shunt-trip coils, H1/H2 closing coils and 52a/52b auxiliary contacts for status indication and interlocking.

Technical Data

Item	Unit	20kA	25kA	31.5kA	40kA	50kA
Rated Voltage	kV	12	12	12	12	12
Rated Current	A	630	1250	1250 1600 2000 2500	1250 1600 2500 3150	1250 2500 3150
Rated Short-Circuit Breaking Current	kA	20	25	31.5	40	50
Rated Short-Circuit Making Current (Peak)	kA	50	63	80	100	125
Rated Short-Time Withstand Current (4 s)	kA	20	25	31.5	40	50
Power Frequency Withstand Voltage (across isolating gap)	kV	48	48	48	48	48
Power Frequency Withstand Voltage (closed position)	kV	42	42	42	42	42
Lightning Impulse Withstand Voltage (across isolating gap)	kV	85	85	85	85	85
Lightning Impulse Withstand Voltage (closed position)	kV	75	75	75	75	75
Mechanical Life	Operations	10000	10000	10000	10000	10000
Operating Mechanism Control Voltage	V	AC/DC 110, 220
Contact Opening Distance	mm	11 ± 1

Selection note: choose the breaking-capacity variant according to the calculated fault level of the installation and the maximum continuous load current. All variants share the same control-voltage options and mechanical characteristics.

Standards

Manufactured and type-tested in accordance with IEC and GB standards for AC high-voltage circuit breakers, including IEC 62271-100, GB 1984 and GB/T 11022.

Technical note: type-test reports and certification documents for the required breaking-capacity variant are available on request.

Installation & Dimensions

Installation Diagram

ZN63 (VS1)-12kV Indoor High Voltage Vacuum Circuit Breaker - installation

The ZN63 (VS1)-12 is available in fixed and withdrawable (handcart) versions for standard switchgear cubicles. The installation requirements are a contact meshing depth of at least 15 mm and a handcart stroke of 200 ± 2 mm, with adequate clearance left for operation and maintenance access.

Dimension	Value (mm)
Handcart Stroke	200 ± 2
Minimum Contact Meshing Depth	≥ 15

Rated Current (A)	630	1250	1600
Rated Short-Circuit Breaking Current (kA)	20, 25	25, 31.5, 40	31.5
Matched Static Contact Size (mm)	φ35	φ49	φ55

Safety notice: always de-energize and earth the circuit before installation or maintenance. Verify correct meshing of moving and static contacts (minimum 15 mm engagement) before closing, and never operate the breaker beyond its rated environmental conditions.

FAQs

Standard breaking-capacity ratings are 20 kA, 25 kA, 31.5 kA, 40 kA and 50 kA, each matched to rated currents from 630 A to 3150 A. Select the rating from the calculated maximum fault level of your system and confirm final parameters with our engineering team.

Standard units are rated for altitudes up to 1000 m and ambient temperatures from -10 °C to +40 °C. For higher altitudes, lower temperatures or large temperature swings, customised versions can be supplied after technical review.

The 31.5 kA breaking-capacity version is offered with rated currents of 1250 A, 1600 A, 2000 A and 2500 A. Verify the continuous load current and upstream protection coordination before ordering.

Every unit passes routine factory tests covering mechanical operation, secondary-wiring correctness and dielectric performance in line with IEC and GB routine-test requirements. Detailed test reports for a specific order are available from our sales team.

Yes. Custom adaptations for severe dust, chemical-corrosive atmospheres and other extreme site conditions are available subject to technical evaluation. Send your site data to our engineering team for confirmation.

It is designed for 12 kV 50 Hz indoor switchgear, in particular KYN28A-12 metal-clad panels, where it serves as the protection and control switching device for distribution feeders, transformer feeders and motor feeders in industrial plants, mines and substations.

Standard designs are suitable for installation sites with seismic intensity up to degree 8. For higher seismic requirements, please advise the site seismic data so that suitable fixing arrangements can be evaluated.

ZN63 (VS1)-12kV Indoor High Voltage Vacuum Circuit Breaker