Circuit Breakers
High‑performance, reliable switching solutions for modern power systems
Switchgear circuit breakers are essential components in high-voltage designed to interrupt fault currents and protect electrical equipment.
Available in Live Tank and Dead Tank designs, these breakers ensure safe and efficient operation across transmission and distribution networks.

- 01 Application Overview
- 02 What We Solve For
Application Overview
The high‑voltage circuit breaker portfolio (40.5kV–500kV) is designed for use in power stations, substations, transmission networks, rail systems, industrial facilities, mining operations, and extreme‑climate environments. These breakers provide safe, reliable switching for:
- Normal load current switching
- Short‑circuit fault interruption
- Back‑to‑back capacitor bank switching (C2 class)
- No-load line and cable charging current switching
- Reactive power compensation applications
- Frequent operation scenarios
- High‑altitude (up to 5000m) and high‑pollution environments (Class IV)
What We Solve For
The circuit breakers address critical challenges in electrical safety and system reliability. They prevent damage caused by overloads, short circuits, and unexpected electrical faults, protecting both equipment and people. By automatically interrupting excessive current flow, they reduce the risk of fires, costly downtime, and maintenance issues. Additionally, they help maintain stable operation across complex electrical networks, ensuring that power is delivered safely and consistently. In short, Insulect circuit breakers provide peace of mind by safeguarding electrical systems against common but potentially dangerous disruptions.
Features & Functionality




Functionality & Options
- Interrupts high short‑circuit currents up to 31.5–63kA to protect system equipment.
- Switches normal load currents across voltage levels from 40.5kV to 500kV.
- Provides C2‑class switching for back‑to‑back capacitor banks and reactor circuits.
- Breaks no‑load line and cable charging currents without restrikes for safe operation.
- Supports frequent operation through robust spring mechanisms and long mechanical life.
Key Technical Specifications
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Rated Voltage: 40.5kV / 72.5kV / 126kV / 145kV / 252kV
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Rated Current: 2500A / 3150A / 4000A / 5000A
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Short‑Circuit Breaking Current: 31.5kA / 40kA / 50kA / 63kA
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Short‑Circuit Duration: 3–4 seconds
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Insulation Levels: Power frequency: 95–552kV; Lightning impulse: 185–1260kV
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Gas System: SF₆ pressure: 0.4–0.7 MPa depending on model
Our Projects featuring Insulect Substations
Explore our project highlights to see where Insulect Substations are making an impact.
For tailored advice on whether this solution suits your network, please connect with our team here.
Where you'll find our Substations
You'll find Insulect-supplied and installed Substations across Australia and New Zealand -- our locally built Insulect range and imported Sieyuan range.







Why Choose Insulect for Circuit Breakers
Services & Support
Insulect offers comprehensive services and support for the products we manufacture and specialise in, enhancing value for local utilities, major energy users, equipment manufacturers, and service operators.
Our local technical team provides exceptional support and expertise, ensuring quick response times and personalised service to tackle any challenges that may arise during project execution.
Our team utilises advanced technology and industry knowledge to develop innovative and efficient high-voltage switchgear solutions, customised to fit the unique requirements of each project.
We facilitate smooth procurement and logistics processes by sourcing from trusted, proven partners and coordinating timely deliveries, ensuring projects remain on schedule and within budget.
We are able to oversee every phase from concept to completion, providing comprehensive solutions that simplify complex projects and ensure successful outcomes.