Product Overview

The Schneider MT32H2 MasterPact Circuit Breaker Frame is a high-current air circuit breaker frame associated with the MasterPact NW32H2 configuration. It is used in low-voltage power distribution systems requiring high current-carrying capacity and short-circuit protection.

The NW32H2 configuration has a rated current of 3200 A and belongs to the H2 breaking performance category. It provides a rated ultimate short-circuit breaking capacity of 100 kA at 440 V AC, making it suitable for main distribution and high-capacity feeder protection in industrial switchgear installations.

The MasterPact NW platform supports three-phase electrical distribution and can be integrated into compatible low-voltage switchboards. The fixed mounting configuration provides a direct installation arrangement within the corresponding switchgear assembly.

The MT32H2 frame is associated with applications where electrical loads require substantial current capacity and coordinated circuit protection. It can be used with compatible MasterPact protection units and operating accessories according to the selected equipment configuration.

When selecting a replacement, engineers should verify the complete NW32H2 configuration, including rated current, breaking capacity, pole arrangement, mounting type, control unit, and electrical connection requirements.

Technical Specifications

Product Features

• 3200 A Current Rating: Supports high-capacity electrical distribution in industrial and commercial switchgear systems.
• H2 Breaking Performance: Provides a 100 kA ultimate short-circuit breaking capacity at 440 V AC.
• Three-Pole Configuration: Supports three-phase power distribution and circuit protection.
• MasterPact NW Compatibility: Belongs to Schneider Electric’s MasterPact NW air circuit breaker platform.
• Fixed Mounting Arrangement: Supports installation in compatible low-voltage switchgear assemblies.
• High Short-Time Withstand Capacity: Supports 85 kA short-time withstand current for 1 second.
• Isolation Capability: Suitable for isolation according to EN/IEC 60947-2.
• Protection Unit Compatibility: Supports compatible MasterPact electronic trip units according to the selected configuration.

Working Principle

The MT32H2 operates as part of the MasterPact NW32H2 air circuit breaker system. It controls the electrical connection between the incoming power supply and the downstream distribution circuit.

During normal operation, current flows through the main contacts of the circuit breaker to supply connected electrical equipment. The breaker remains closed while the electrical conditions stay within the permitted operating limits.

When an overload or short circuit occurs, the associated protection unit detects the abnormal current condition and initiates the tripping mechanism. The main contacts separate, interrupting the electrical circuit.

As the contacts open, an electrical arc forms between them. The air arc-extinguishing system controls and extinguishes the arc, allowing the circuit breaker to interrupt the fault current.

The NW32H2 configuration provides a rated ultimate short-circuit breaking capacity of 100 kA at 440 V AC. This capability is particularly relevant to installations where the prospective fault current is high.

Typical Protection Sequence:

Incoming Power Supply → MT32H2 MasterPact Circuit Breaker → Main Distribution Busbar → Downstream Feeder Circuits

After a fault interruption, the cause of the trip should be investigated before the breaker is reset and returned to service.

Role in Schneider MasterPact Power Distribution Architecture

The MT32H2 serves as a main or feeder circuit protection component in compatible MasterPact NW32H2 low-voltage distribution systems.

In a typical switchgear installation, the circuit breaker is positioned between the incoming electrical supply and the downstream distribution busbar. It provides switching and fault interruption functions for high-current electrical circuits.

Its 3200 A rating and H2 interruption performance make it suitable for distribution systems with substantial electrical loads and high prospective short-circuit currents.

Industrial Applications

Installation and Maintenance

1. Verify Model Configuration: Confirm that MT32H2 corresponds to the required MasterPact NW32H2 configuration, including rated current, breaking capacity, and pole arrangement.
2. Check Switchgear Compatibility: Verify the fixed mounting arrangement and electrical connection requirements against the existing switchgear assembly.
3. Isolate the Power Supply: Disconnect the upstream power source and apply the required lockout and tagout procedures.
4. Verify Absence of Voltage: Use an appropriately rated voltage tester to confirm that all relevant electrical connections are de-energized.
5. Inspect Main Connections: Examine incoming and outgoing connection points for overheating, oxidation, corrosion, or mechanical damage.
6. Check Protection Configuration: Verify the installed protection unit and its settings against the electrical coordination requirements.
7. Inspect Operating Mechanism: Check the opening, closing, and stored-energy operating functions according to the applicable maintenance instructions.
8. Check Auxiliary Accessories: Inspect auxiliary contacts, shunt releases, undervoltage releases, and other installed accessories.
9. Verify Mounting Security: Confirm that the circuit breaker is correctly positioned and secured within the switchgear assembly.
10. Perform Electrical Testing: Carry out the required insulation, contact resistance, and protection function tests using approved procedures.
11. Conduct Operational Checks: Verify mechanical and electrical operating functions before returning the equipment to service.
12. Document Maintenance Results: Record the breaker configuration, protection settings, inspection findings, test results, and maintenance date.

Compatible System Components

Recommended Related Models

Key Advantages

• 3200 A rated current for high-capacity electrical distribution.
• H2 performance with 100 kA breaking capacity at 440 V AC.
• Three-pole configuration for three-phase power systems.
• Fixed mounting arrangement for compatible switchgear installations.
• Supports overload and short-circuit protection.
• Compatible with the MasterPact NW protection and accessory ecosystem.
• Suitable for industrial and commercial low-voltage distribution applications.

Technical FAQs

1. What is the rated current of the MT32H2?

The associated MasterPact NW32H2 configuration has a rated current of 3200 A at 40 °C. This rating distinguishes it from the NW25H2 configuration, which is rated at 2500 A.

2. What does the H2 performance level mean?

H2 identifies the circuit breaker’s short-circuit breaking performance. The NW32H2 provides a rated ultimate short-circuit breaking capacity of 100 kA at 440 V AC and 85 kA at 690 V AC.

3. Can the MT32H2 operate without an electronic protection unit?

The specified configuration is without a control unit. A compatible protection unit must be selected according to the required overload, short-circuit, and other protection functions of the electrical installation.

4. What is the difference between NW32H2 fixed and drawout configurations?

The fixed configuration is installed directly into the switchgear assembly, whereas the drawout configuration uses a withdrawable mounting arrangement that allows the breaker to be moved between connected, test, and disconnected positions. The mounting configuration must match the existing switchgear design.