Medium- and high-voltage electrical systems require standardized requirements for switchgear design, testing, ratings, and operation. The IEC 62271 series is one of the key international standards families for high-voltage switchgear and controlgear.

IEC 62271 switchgear refers to switchgear and controlgear designed and tested according to the applicable requirements of the IEC 62271 series. The series covers equipment such as AC circuit breakers, metal-enclosed switchgear, disconnectors, earthing switches, and other high-voltage switching equipment.

IEC 62271 is not a single product standard. It is a series of standards, with different parts addressing different types of equipment and requirements.

For buyers, understanding the applicable part of IEC 62271 is therefore more useful than simply asking whether a product is “IEC 62271 compliant.”

What Is IEC 62271?

IEC 62271 is an International Electrotechnical Commission (IEC) standards series covering high-voltage switchgear and controlgear.

The series addresses equipment used in:

• Electrical substations
• Distribution networks
• Transmission systems
• Industrial power systems
• Renewable-energy plants
• Data centers
• Battery energy storage systems
• Commercial and infrastructure projects

The applicable standard depends on the equipment type.

For example, the requirements for an AC circuit breaker are different from those for metal-enclosed switchgear.

This is why a technical specification should identify the relevant IEC 62271 part rather than only stating “IEC 62271.”

Which Switchgear Uses IEC 62271?

The IEC 62271 family covers a broad range of high-voltage switching and control equipment.

Examples include:

• AC circuit breakers
• Metal-enclosed switchgear
• Disconnectors
• Earthing switches
• Gas-insulated switchgear
• Instrument transformers associated with switchgear applications
• Other specialized high-voltage switching equipment

The exact applicability depends on the product and its voltage classification.

For medium-voltage projects, standards within the IEC 62271 family are frequently referenced in switchgear specifications.

Key Parts of the IEC 62271 Series

The IEC 62271 series contains multiple parts.

Some particularly relevant standards include:

This is not an exhaustive list. The applicable edition and standard should always be verified against the project specification and the current IEC publication.

IEC 62271-200 for Metal-Enclosed AC Switchgear

IEC 62271-200 is particularly relevant when specifying metal-enclosed AC switchgear for medium-voltage distribution systems.

It applies to metal-enclosed switchgear and controlgear for AC applications within its stated voltage range.

Typical applications include:

• Distribution substations
• Industrial facilities
• Solar substations
• Wind farm substations
• Data centers
• Commercial buildings
• Battery energy storage systems

Internal Arc Classification

One important subject associated with IEC 62271-200 is internal arc classification (IAC).

Internal arc classification concerns the behavior of suitable metal-enclosed switchgear under specified internal arcing conditions.

Depending on the design and test configuration, the classification considers factors such as:

• Accessibility
• Installation arrangement
• Tested duration
• Arc current
• Personnel protection criteria

An IAC designation should not be interpreted as meaning that all possible arc faults are harmless. It describes performance under the specified test conditions.

IEC 62271-100 for AC Circuit Breakers

IEC 62271-100 addresses AC circuit breakers.

Circuit breakers are designed to make, carry, and interrupt electrical currents under specified operating conditions.

In an MV switchgear lineup, the circuit breaker is one of the primary devices used for:

• Fault interruption
• Load switching
• Transformer protection
• Feeder protection
• Bus-section switching

Vacuum circuit breakers are widely used in modern medium-voltage applications.

When specifying a VCB, buyers should evaluate the complete breaker and switchgear assembly against the applicable requirements rather than treating the vacuum interrupter as the entire compliance assessment.

IEC 62271-1 Common Specifications

IEC 62271-1 establishes common specifications for applicable high-voltage switchgear and controlgear.

Depending on the equipment, these specifications can relate to:

• Service conditions
• Rated values
• Design requirements
• Dielectric characteristics
• Temperature-rise requirements
• Mechanical operation
• Testing
• Documentation

The specific product standard should be considered together with the common requirements.

IEC 62271 Ratings for Switchgear

When purchasing IEC 62271 switchgear, rated voltage is only one of the parameters to review.

Important electrical ratings can include:

Rated Voltage

The rated voltage defines the voltage level for which the equipment is designed.

Common MV classes can include:

• 12 kV
• 24 kV
• 36 kV

The appropriate rating depends on the actual network and applicable standard.

Rated Current

Rated current indicates the continuous current the equipment is designed to carry under specified conditions.

It must be coordinated with:

• Transformer capacity
• Feeder load
• Busbar capacity
• Expected operating current

Short-Circuit Breaking Current

For circuit breakers, the short-circuit breaking capability is a critical parameter.

It must be suitable for the prospective fault current at the installation point.

Short-Time Withstand Current

This indicates the current the equipment can withstand for a specified short duration under the applicable test conditions.

Peak Withstand Current

This relates to the equipment’s ability to withstand the peak current associated with short-circuit conditions.

Insulation Levels

The insulation system must be suitable for the system voltage and specified dielectric requirements.

Relevant parameters can include:

• Power-frequency withstand voltage
• Lightning impulse withstand voltage

IEC 62271 Type Tests and Routine Tests

Testing is an important part of switchgear qualification and manufacturing.

The applicable tests depend on the equipment and standard.

Type Tests

Type tests are used to verify the performance of a representative design under specified conditions.

Depending on the product, tests can address areas such as:

• Dielectric performance
• Temperature rise
• Short-circuit performance
• Mechanical operation
• Internal arc performance where applicable
• Protection against environmental effects
• Other design-specific characteristics

A type-test report should be reviewed for the actual equipment configuration and ratings.

Routine Tests

Routine tests are performed on individual manufactured units or assemblies as required by the applicable standard.

They help verify that the manufactured equipment conforms to specified requirements.

Depending on the equipment, routine testing can include:

• Dielectric tests
• Wiring checks
• Mechanical operation
• Control-circuit verification
• Measurement of relevant characteristics

The specific test program should be confirmed against the applicable edition of the standard.

IEC 62271 and SF6-Free Switchgear

IEC 62271 does not mean that switchgear must use SF6.

The standards specify applicable technical and performance requirements; they do not automatically require one particular insulation or interruption technology for every application.

This allows manufacturers to develop different technologies, including:

• Vacuum interruption
• Air insulation
• Solid insulation
• Alternative gas technologies

For example, a medium-voltage switchgear assembly can use vacuum circuit breakers without requiring SF6 inside the vacuum interrupter.

However, when evaluating an SF6-free switchgear product, buyers should verify the entire assembly, including its insulation system, compartments, auxiliary components, and technical documentation.

How to Specify IEC 62271 Switchgear

A good procurement specification should identify the equipment, applicable standard, electrical ratings, environmental conditions, and required testing.

1. Identify the Equipment

Specify whether the requirement is for:

• Metal-enclosed switchgear
• Circuit breaker
• Disconnector
• Earthing switch
• RMU
• GIS
• Prefabricated substation

Different equipment can have different applicable IEC 62271 parts.

2. Specify the Voltage

Define:

• Rated voltage
• System voltage
• Frequency
• Insulation level

For example, a project might require a specific MV voltage class such as 12 kV, 24 kV, or 36 kV.

3. Define Current and Fault Ratings

Specify:

• Rated normal current
• Short-circuit breaking current
• Short-time withstand current
• Peak withstand current

These values should come from the project’s electrical calculations.

4. Define Installation Conditions

Include:

• Indoor or outdoor
• Ambient temperature
• Altitude
• Humidity
• Pollution level
• Seismic requirements where applicable

5. Define Protection

Specify the required:

• Protection relays
• CTs
• VTs
• Interlocking
• Trip circuits
• Control circuits

6. Define Testing and Documentation

Request appropriate:

• Type-test documentation
• Routine-test reports
• Drawings
• Datasheets
• Operation manuals
• Maintenance instructions
• Certificates and declarations where applicable

Applications of IEC 62271 Switchgear

IEC 62271 equipment can be found across many electrical infrastructure projects.

Solar Substations

Solar farms use MV and HV switchgear for:

• Collector feeders
• Transformer protection
• Grid interconnection
• Switching and isolation

Wind Farm Substations

Wind farms use switchgear to collect turbine output and connect the plant to the grid.

Data Centers

Data centers can use MV switchgear at utility and substation interfaces and LV equipment for downstream distribution.

Battery Energy Storage

BESS projects can use MV switchgear between transformers, PCS equipment, collector systems, and the grid.

Industrial Facilities

Factories and processing plants use MV switchgear for:

• Motor feeders
• Transformers
• Incoming supplies
• Distribution feeders

IEC 62271 Switchgear Selection Checklist

Before purchasing, buyers should verify:

Standards

• Applicable IEC 62271 part
• Current applicable edition
• Local regulations
• Utility requirements

Electrical

• Rated voltage
• Rated current
• Short-circuit rating
• Insulation level
• Frequency
• Withstand ratings

Mechanical

• Enclosure
• Dimensions
• Cable entry
• Operating mechanism
• Interlocking

Protection

• Protection relay
• CT/VT configuration
• Trip and close circuits
• Protection coordination

Environmental

• Indoor/outdoor
• Ambient temperature
• Altitude
• Pollution
• Humidity
• Corrosion

Sustainability

• SF6-free requirement
• Insulation technology
• Environmental documentation

Testing

• Type-test evidence
• Routine tests
• Factory acceptance testing
• Project-specific tests

Frequently Asked Questions

What is IEC 62271 switchgear?

IEC 62271 switchgear is switchgear and controlgear designed and tested according to the applicable requirements of the IEC 62271 standards series. The relevant part depends on the type of equipment.

Is IEC 62271 a single standard?

No. IEC 62271 is a family of standards covering different types of high-voltage switchgear and controlgear and their technical requirements.

What is IEC 62271-200?

IEC 62271-200 covers AC metal-enclosed switchgear and controlgear within its specified voltage range, including equipment used in many medium-voltage distribution applications.

What is IEC 62271-100?

IEC 62271-100 specifies requirements for AC circuit breakers.

Does IEC 62271 require SF6?

No. IEC 62271 does not require every applicable switchgear product to use SF6. Different interruption and insulation technologies can be used when they meet the applicable technical requirements.

Can vacuum circuit breakers comply with IEC 62271?

Yes. Vacuum circuit breakers can be designed and tested according to applicable IEC 62271 requirements.

Does IEC 62271 cover RMUs?

The applicable IEC 62271 requirements depend on the RMU design and equipment configuration. The relevant standard and edition should be identified from the manufacturer’s technical documentation.

What voltage levels are covered by IEC 62271?

The IEC 62271 family covers different equipment and voltage ranges. For example, IEC 62271-200 addresses metal-enclosed AC switchgear and controlgear above 1 kV and up to and including 52 kV.

What is IAC in IEC 62271-200?

IAC means Internal Arc Classification. It indicates the tested internal-arc performance of applicable metal-enclosed switchgear under specified test conditions and accessibility arrangements.

What should I request from a switchgear manufacturer?

Request the applicable IEC standard and edition, technical datasheet, type-test evidence where applicable, routine-test documentation, drawings, protection information, environmental ratings, and project-specific compliance documentation.

Is IEC 62271 certification enough to select switchgear?

Not by itself. Buyers should also verify voltage, current, fault ratings, installation conditions, protection requirements, utility specifications, project standards, and compatibility with the complete electrical system.

Is IEC 62271 applicable to data center switchgear?

It can be. MV switchgear used in data center substations or utility interfaces may fall under applicable IEC 62271 standards, depending on the equipment and project requirements.

Conclusion

IEC 62271 switchgear is not a single product or a single certification. It is a family of international standards covering different types of high-voltage switchgear and controlgear.

For a successful switchgear specification, buyers should identify the relevant standard, such as:

• IEC 62271-1 for common specifications
• IEC 62271-100 for AC circuit breakers
• IEC 62271-102 for disconnectors and earthing switches
• IEC 62271-200 for applicable metal-enclosed MV switchgear
• Other IEC 62271 parts for specific equipment

The equipment should then be evaluated against its rated voltage, current, short-circuit capability, insulation levels, environmental conditions, protection system, testing requirements, and grid or utility specifications.

For modern applications such as solar farms, wind farms, BESS, data centers, and industrial substations, IEC 62271 provides an important technical framework for specifying and evaluating switchgear.