Indoor AC High Voltage Vacuum Load Breaker with Earthing Switch

Indoor AC High Voltage Vacuum Load Breaker with Earthing switch by Sangao are suitable for three-phase AC50Hz ring network or terminal power supply  and industrial electric equipments, it's mainly used for load control and short-circuit protection. The load break switch makes and breaks the  load current, closed-loop current, no-load transformer and cable charging current. The combination can break any current up to rated shortcircuit current. The directly-acting isolating distance and arc-extinguishing chamber are linked, with manual and electrical function. Its unique drive mechanism enables the arc-extinguishing chamber to bear high voltage only at the moment of closing and making, which realizes small volume and light weight.

What's  Vacuum Load Breaker?

This Indoor AC High Voltage Vacuum Load Breaker with Earthing Switch is a three‑phase AC 50Hz indoor switching device for ring network, terminal power supply, and industrial equipment applications. The unit employs a vacuum interrupter for arc extinction and a spring operating mechanism (manual or electrical). An optional earthing switch with mechanical interlock and grounding shutter provides visible isolation for maintenance. When fitted with fuses, the assembly interrupts short‑circuit currents via striker‑pin actuation. Rated voltage 12 kV, rated current 630 A, short‑time withstand current 20 kA.

Product Functions

Load current switching

Indoor AC High Voltage Vacuum Load Breaker with Earthing Switch makes and breaks load currents up to 630A under normal operating conditions, covering typical feeder and transformer loads.

Closed‑loop current switching

Switches closed‑loop currents in ring network configurations, enabling load transfer between feeders without interrupting supply to downstream customers.

No‑load transformer current switching

Our outdoor High Voltage Disconnecting Vacuum Break Load Switch makes and breaks no‑load currents of transformers up to 1600kVA capacity, corresponding to the magnetizing inrush and steady‑state excitation current levels of distribution transformers.

Cable charging current switching

Makes and breaks cable charging currents for underground or overhead cable sections, allowing energization and de‑energization of cable feeders.

Short‑circuit protection (with fuses)

When configured with current‑limiting fuses, the striker‑pin mechanism of the fuse actuates the switch trip bar, opening all three phases upon fault detection. The assembly can interrupt any current up to the rated short‑circuit value, providing a secondary protection layer where upstream breakers or relays are the primary fault clearing devices.

Maintenance isolation

The integrated earthing switch, when closed, provides a visible earth connection on the load side. The grounding shutter physically blocks access to live parts, allowing maintenance personnel to verify isolation and work safely on downstream equipment.

Load Break Switch vs. Vacuum Circuit Breaker

Technical Parameters

Structural Design

Direct‑acting isolating distance and arc‑extinguishing chamber linkage
The isolating gap and the vacuum interrupter are mechanically linked to operate in a single motion. This ensures the visible break is always accompanied by a fully opened interrupter.

Drive mechanism

The interrupter is energised only at the instant of closing and opening, reducing electrical stress on the vacuum chamber. This allows a more compact interrupter size and extends contact life.

Grounding shutter

A metal shutter is positioned between the fixed and moving contact tubes and is interlocked with the earthing switch. When the earthing switch is closed, the shutter physically isolates the live parts, providing a visible and verifiable earth connection for maintenance.

Mechanical interlock

Prevents closing the earthing switch unless the main contacts are open, and prevents opening the main contacts while the earthing switch is closed.

Application Fields

Indoor AC High Voltage Vacuum Load Breaker with Earthing Switch has great compatibilities:

1. Urban ring‑main units (RMUs) for sectionalising and load switching.

2. Transformer incomer panels and feeder cabinets in industrial distribution.

3. Terminal supply points in radial networks.

4. Rural distribution networks – the unit can be used to sectionalise long feeders, reducing outage zones and allowing voltage regulation via capacitor bank switching.

5. Indoor installations in metal‑enclosed switchgear; vacuum technology eliminates SF6 gas use and associated environmental concerns.

Company Profile and Manufacturing Capability

Facility: 10‑mu (6,667 m²) site in Liushi, Zhejiang, with 10,000 m² of production floor space.

Workforce: 120 employees, including 20 mid‑to‑senior technical professionals. Registered capital RMB 81.68 million, total assets approximately RMB 200 million.

Certifications: ISO 9001:2008 (quality), ISO 14001 (environment), ISO 45001 (occupational health and safety).

Process control: ERP system for material procurement, manufacturing, and traceability. Routine testing includes dielectric withstand, mechanical operation, and contact resistance checks on every unit.

Technical partnerships: Collaborations with Xi'an Senyuan, Beijing Electrical Research Institute, and Xi'an High Voltage Research Institute for type testing and standard compliance.

FAQ

Q1: Can this Indoor AC High Voltage Vacuum Load Breaker with Earthing Switch replace a vacuum circuit breaker?
No. It is designed for load switching only. For short‑circuit protection, it must be paired with fuses or rely on upstream circuit breakers.

Q2: What maintenance is required for the vacuum interrupter?
The vacuum interrupter is sealed and maintenance‑free. Routine checks involve mechanical operation, lubrication, and interlock verification.

Q3: Is the earthing switch standard or optional?
The earthing switch is optional (designated D). When specified, it is mechanically interlocked with the main contacts for safe maintenance.

Q4: What is the typical lead time and customization possibility?
Standard units with spring mechanism and earthing switch are shipped within 4‑6 weeks. Customisations (auxiliary contacts, mounting, mechanism modifications) are available upon request.

Technical Parameters

You can check two version of parameters data for our Handcart Type Vacuum Load Break Switch with Disconnecting Switch Combination below:

Indoor AC High Voltage Vacuum Load Breaker with Earthing switch by Sangao are suitable for three-phase AC50Hz ring network or terminal power supply  and industrial electric equipments, it's mainly used for load control and short-circuit protection. The load break switch makes and breaks the  load current, closed-loop current, no-load transformer and cable charging current. The combination can break any current up to rated shortcircuit current. The directly-acting isolating distance and arc-extinguishing chamber are linked, with manual and electrical function. Its unique drive mechanism enables the arc-extinguishing chamber to bear high voltage only at the moment of closing and making, which realizes small volume and light weight.

Outline and Installation Size&Component Breakdown

No.	Component
1	Fixed contact
2	Insulating cover
3	Shutter
4	Chassis
5	Vacuum arc‑extinguishing chamber
6	Guide plate
7	Fuse
8	Energy storage shaft
9	Earth switch shaft
10	Operation panel