Product Overview

The Schneider Electric MT20N2 Circuit Breaker is identified with the Masterpact MT family of low-voltage air circuit breakers (ACBs). Designed for high-capacity electrical distribution systems, this type of circuit breaker is used to protect electrical networks, switchboards, and connected equipment against abnormal current conditions.

Air circuit breakers are commonly installed in main distribution panels, industrial switchboards, generator distribution systems, and large commercial electrical installations. They provide circuit switching and protection functions for systems operating at substantial current levels. Depending on the selected configuration, an ACB can provide protection against overloads and short circuits while also supporting electrical isolation and controlled switching operations.

The MT20N2 designation is associated with a 2000 A rated-current class in Masterpact MT product listings. The N2 designation identifies a particular breaking-capacity configuration within the product family. However, the complete electrical characteristics depend on the exact breaker version, including its pole arrangement, trip unit, mounting configuration, and applicable product standard.

The MT20N2 is intended for integration into appropriately engineered low-voltage distribution systems. Its selection must take account of the system’s operating voltage, rated current, prospective short-circuit current, protection coordination, and installation requirements.

For maintenance and replacement projects, identifying the complete product configuration is essential. Circuit breakers within the same product family may differ in rated current, breaking capacity, trip-unit functions, fixed or drawout mounting, and electrical accessories.

Technical Specifications

Important: The table distinguishes the model-family identification from configuration-dependent specifications. Confirm the complete catalog number and nameplate before using the breaker in an electrical design. The supplied dimensions and weight are listing values and should be checked against the actual unit.

Function and Working Principle

The Schneider Electric MT20N2 is an air circuit breaker intended to control and protect a low-voltage electrical circuit. Its operating principle involves establishing, carrying, and interrupting current through a mechanical switching system.

When the breaker is closed, its contacts provide a conductive path for current to flow through the protected circuit. When an abnormal electrical condition is detected by the installed protection system, the trip mechanism can initiate contact separation to interrupt the current.

1. Overload Protection

An overload occurs when current exceeds the permitted operating level for a sustained period. If an overload is not cleared, cables, busbars, transformers, and connected equipment may experience excessive heating.

An appropriately configured trip unit monitors current and applies the selected protection settings. When the measured current exceeds the configured overload threshold for the specified duration, the breaker trips and disconnects the protected circuit.

The actual overload protection characteristics depend on the installed trip unit and its settings.

2. Short-Circuit Protection

A short circuit can cause a very high current to flow through an electrical system. This may produce substantial thermal and mechanical stress on conductors and electrical equipment.

The circuit breaker’s protection system detects short-circuit conditions and initiates interruption according to the configured protection characteristics.

The breaker must have an adequate rated breaking capacity for the prospective fault current at its installation point. The N2 designation should therefore be checked against the manufacturer’s technical documentation for the exact breaker configuration and applicable voltage.

3. Circuit Switching

An air circuit breaker can also be used for controlled switching of electrical distribution circuits. In a properly designed switchboard, the breaker may serve as an incoming main breaker, bus-section breaker, or outgoing feeder breaker.

Its switching function allows operators and maintenance personnel to control the connection between the electrical supply and the protected circuit, subject to the equipment’s operating instructions and electrical safety procedures.

4. Electrical Isolation

Depending on the specific version and applicable standards, a suitable Masterpact breaker configuration may support isolation functions.

Isolation requirements should be confirmed from the breaker markings and manufacturer documentation. A circuit breaker should not automatically be treated as the sole means of safe maintenance isolation unless the complete installation and applicable procedures permit it.

5. Protection Coordination

In a distribution system containing multiple circuit breakers, protection coordination helps ensure that the device closest to a fault operates where possible, limiting the interruption to the affected section.

The trip-unit settings of the MT20N2 must be coordinated with upstream and downstream protective devices. Correct coordination helps maintain continuity of service for unaffected equipment.

Role in Industrial Power Distribution Systems

The MT20N2 can serve as a major switching and protection component in a low-voltage electrical distribution system.

Main Incoming Protection

In an industrial facility, the main incoming breaker connects the incoming electrical supply to the main distribution busbar. A suitably rated ACB can protect the main distribution circuit and provide a controlled switching point.

The final selection depends on the supply transformer, rated system current, fault level, and protection philosophy.

Feeder Circuit Protection

A circuit breaker installed on an outgoing feeder protects the distribution circuit supplying downstream equipment. Depending on the switchboard design, the breaker may supply motor control centers, process distribution panels, auxiliary power systems, or other electrical loads.

The trip settings must be coordinated with downstream protection devices to reduce unnecessary interruption.

Generator and Transformer Distribution

Large industrial electrical systems may use circuit breakers to connect generators, transformers, and distribution busbars. ACBs can form part of these arrangements when their electrical ratings and protection functions meet the system design requirements.

Generator and transformer applications require particular attention to short-circuit behavior, protection settings, and switching sequences.

Integration with Supervisory Systems

Some Masterpact configurations can be equipped with auxiliary contacts, electrical operating accessories, and communication-related components. These options may allow breaker status and selected operating information to be incorporated into a supervisory system.

The availability of these functions depends on the exact breaker configuration and installed accessories. The MT20N2 model designation alone does not confirm that communication or remote-control hardware is present.

Industrial Applications

1. Manufacturing Facilities

Manufacturing plants rely on stable electrical distribution to operate production machinery, control cabinets, motors, and auxiliary systems.

A suitably configured 2000 A-class air circuit breaker may be used in a main distribution board or a major feeder circuit. Its protection settings should be coordinated with the plant’s electrical network.

2. Power Distribution Switchboards

Low-voltage switchboards distribute electrical power to different sections of an industrial or commercial facility.

The MT20N2 may be considered for an appropriately rated incoming or outgoing circuit position, subject to busbar compatibility, mounting arrangement, and electrical specifications.

3. Data Centers and Critical Infrastructure

Data centers require carefully designed power distribution systems to support servers, cooling equipment, UPS systems, and auxiliary electrical loads.

Air circuit breakers may be used in main or feeder distribution assemblies where their ratings and protection functions match the electrical design. Selectivity and maintenance planning are particularly important in these installations.

4. Utility and Infrastructure Installations

Water treatment facilities, transportation infrastructure, and other utility installations use low-voltage distribution systems to supply pumps, ventilation equipment, control systems, and auxiliary loads.

A suitable ACB can provide switching and protection within these systems, helping maintenance teams isolate or manage individual distribution sections.

5. Commercial and Industrial Buildings

Large commercial buildings and industrial complexes may use high-capacity circuit breakers in main switchboards and electrical distribution rooms.

The breaker must be selected according to the installation’s load demand, fault level, operating voltage, and protection coordination requirements.

Installation and System Integration

Correct installation is essential for circuit breaker performance, electrical safety, and long-term reliability.

1. Verify the Complete Model

Before installation, confirm the full product designation and the information on the breaker nameplate.

Important details include:

• Rated current.
• Rated operational voltage.
• Rated insulation voltage.
• Rated breaking capacity.
• Number of poles.
• Fixed or drawout mounting arrangement.
• Installed trip unit.
• Auxiliary contacts and electrical accessories.

Do not rely solely on the MT20N2 designation when preparing an electrical installation.

2. Confirm Switchboard Compatibility

The breaker must match the switchboard’s mechanical and electrical design. Check the mounting arrangement, busbar connections, terminal configuration, clearances, and required operating accessories.

For drawout versions, verify the compatibility of the cradle and associated connection system. For fixed versions, confirm the mounting and conductor connection requirements.

The supplied dimensions of 301 × 196 × 276 mm should be checked against the actual breaker and its installation drawings before designing a panel or replacement arrangement.

3. Check Electrical Ratings

Verify that the rated voltage and current are suitable for the electrical network. The breaker must also have an adequate breaking capacity for the prospective short-circuit current at the installation point.

Rated current alone is not sufficient to establish suitability. Engineers must consider the system’s fault level, ambient temperature, installation conditions, and protection coordination.

4. Configure the Protection Unit

The installed trip unit determines the available protection functions and adjustment ranges.

Depending on the specific trip-unit version, protection settings may include long-time overload protection, short-time protection, instantaneous protection, and ground-fault protection.

Settings must be calculated according to the electrical system design. Incorrect protection settings can result in nuisance tripping or inadequate protection.

5. Inspect Electrical Connections

Check the condition of busbar connections, terminals, conductors, and contact surfaces. Loose or damaged connections can create excessive resistance and localized heating.

Connection torque, conductor sizing, and installation procedures must follow the manufacturer’s instructions.

6. Commissioning and Functional Testing

Before energizing the installation, qualified personnel should verify the mechanical condition, electrical connections, trip-unit settings, interlocks, and accessory operation.

Testing should follow the manufacturer’s procedures and applicable electrical safety standards. Record the final settings and commissioning results for future maintenance.

Compatible System Components

The MT20N2 is normally integrated into a larger low-voltage distribution assembly. The following components may be used in a compatible system, depending on the switchboard design and exact breaker configuration.

Not all accessories are supplied with every MT20N2 breaker. The actual bill of materials should be checked before procurement.

Alternative Models and Replacement Considerations

When replacing an MT20N2, the replacement should be selected according to the complete electrical and mechanical requirements rather than the rated current alone.

Before selecting a replacement, compare:

• Rated operational voltage.
• Rated current.
• Rated breaking capacity.
• Number of poles.
• Fixed or drawout installation.
• Trip-unit type and protection functions.
• Busbar and terminal arrangement.
• Auxiliary contacts and electrical accessories.
• Mechanical interlocking requirements.
• Switchboard dimensions and clearances.
• Applicable electrical standards.

A breaker with the same rated current is not necessarily a direct replacement. Differences in frame size, fault ratings, connection positions, and trip-unit functions may require switchboard modifications.

Key Advantages

High-Current Distribution Capability

The MT20N2 designation is associated with the 2000 A current class, making it relevant to high-capacity low-voltage distribution applications when the exact configuration meets the system requirements.

Circuit Protection

With a suitable protection unit, the breaker can protect electrical circuits against overloads and short circuits according to the configured settings.

Industrial Switching Function

The air circuit breaker can serve as a switching point in main distribution boards and major feeder circuits.

Integration into Distribution Assemblies

The Masterpact MT family is designed for use in low-voltage switchboard applications. The exact mechanical arrangement and accessories must be verified for each installation.

Configurable Protection

The available protection functions depend on the installed trip unit, allowing engineers to select an appropriate protection arrangement for the electrical system.

Maintenance and Replacement Applications

Accurate identification of the breaker model and installed accessories helps maintenance teams assess replacement requirements and manage existing electrical distribution equipment.

Technical FAQs

1. What is the Schneider Electric MT20N2?

The MT20N2 is an air circuit breaker designation associated with the Schneider Electric Masterpact MT family. It is used in low-voltage electrical distribution systems for switching and circuit protection.

2. What is the rated current of the MT20N2?

The MT20N2 designation is associated with a 2000 A rated-current class in product listings. The actual nameplate rating should always be checked before installation.

3. What does N2 mean in MT20N2?

N2 identifies a breaking-capacity configuration within the Masterpact MT family. The corresponding short-circuit ratings depend on the exact breaker version and applicable product standard.

4. Is the MT20N2 an air circuit breaker?

Yes. It is identified as an ACB, or air circuit breaker, intended for low-voltage power distribution applications.

5. What protection functions does it provide?

The available protection functions depend on the installed trip unit. Typical ACB protection arrangements may include overload and short-circuit protection, with additional functions depending on the trip-unit version.

6. Can the MT20N2 be used as a main circuit breaker?

It may be used as a main breaker in a suitably engineered distribution system if its rated current, voltage, breaking capacity, and protection characteristics meet the installation requirements.

7. Does the MT20N2 support remote operation?

Remote operation depends on the installed electrical operating mechanism and accessories. The model designation alone does not confirm that motorized operation or communication hardware is included.

8. What should be checked before purchasing a replacement?

Confirm the complete model designation, nameplate ratings, pole count, mounting arrangement, trip unit, accessories, physical dimensions, and condition. Also verify compatibility with the existing switchboard.

9. Can another 2000 A breaker replace the MT20N2?

Not automatically. The replacement must also meet the required breaking capacity, operating voltage, connection arrangement, protection coordination, and mechanical mounting requirements.

10. Are the listed dimensions and weight sufficient for installation planning?

They can be used as preliminary listing information, but they should not replace the manufacturer’s installation drawing. Verify whether the measurements describe the complete breaker, a subassembly, or a packaged product.

Procurement and Maintenance Recommendations

When sourcing the Schneider Electric MT20N2, begin by identifying the complete breaker configuration. Request clear photographs of the nameplate, front panel, terminals, trip unit, and any installed accessories.

For used or refurbished equipment, inspect the breaker housing, operating mechanism, contact condition, arc chambers, terminals, and mechanical interlocks. Where available, review maintenance records and functional test reports.

Confirm whether the unit is fixed or drawout and whether it includes the required cradle, auxiliary contacts, motor mechanism, shunt trip, undervoltage release, and protection unit. These components can materially affect installation compatibility and the final procurement cost.

During routine maintenance, follow the manufacturer’s procedures for inspection, cleaning, mechanical operation, connection checks, and protection-unit testing. Maintenance intervals should reflect the operating environment, switching frequency, and equipment condition.

For replacement projects, coordinate the breaker with the existing busbar system, upstream and downstream protection devices, and switchboard layout. Electrical installation and commissioning should be carried out by qualified personnel in accordance with the applicable standards and safety procedures.

Conclusion

The Schneider Electric MT20N2 is a Masterpact MT air circuit breaker designation associated with the 2000 A current class. It is intended for low-voltage electrical distribution applications where reliable switching and appropriately configured circuit protection are required.

Its suitability for a particular installation depends on the complete breaker configuration, including rated voltage, breaking capacity, pole arrangement, mounting type, and installed trip unit. For industrial procurement and replacement projects, verifying these details against the nameplate and manufacturer documentation is essential for safe integration and reliable operation.