Product Overview

The Schneider NW08N2 MasterPact NW Circuit Breaker is a low-voltage power circuit breaker designed for electrical distribution and protection in industrial and commercial power systems. It belongs to the Schneider Electric MasterPact NW family, a range of air circuit breakers developed for applications requiring high-current switching, overload protection, and short-circuit protection.

Circuit breakers are essential components in electrical distribution networks. They help protect cables, busbars, transformers, motors, and other electrical equipment by interrupting current when abnormal electrical conditions occur. In large distribution systems, an air circuit breaker can also serve as an incoming, outgoing, or bus-coupling protection device.

The NW08 designation corresponds to an 800 A frame rating in the MasterPact NW family. The circuit breaker is intended for installation in low-voltage switchboards and power distribution assemblies. Its suitability for a particular system depends on the actual rated operational voltage, sensor rating, trip unit, pole configuration, short-circuit breaking capacity, and mounting arrangement.

The supplied product dimensions are 352 × 537 × 297 mm, with a listed weight of 65 kg. These values correspond to the reference dimensions and approximate weight for a fixed-mounted, four-pole NW08 configuration. The actual dimensions and weight should be checked against the delivered unit because fixed and drawout versions, as well as different pole configurations, have different mechanical characteristics.

The MasterPact NW platform is used in applications where dependable electrical protection and coordinated distribution are important. It can be incorporated into main distribution boards, industrial switchgear, power generation facilities, infrastructure systems, and large commercial electrical installations.

Technical Specifications

Important: NW08 identifies the 800 A frame class, not necessarily the exact sensor or trip-unit rating. Confirm the complete catalog designation, pole count, rated voltage, interrupting capacity, and trip-unit configuration before installation or replacement.

Function and Working Principle

The Schneider NW08N2 is designed to provide switching and electrical protection within a low-voltage power distribution system. Its operation involves monitoring current conditions and interrupting the circuit when the protection system detects an abnormal condition.

1. Overload Protection

An overload occurs when an electrical circuit carries more current than its permitted operating level for an extended period.

For example, an industrial distribution feeder may experience excessive current when additional equipment is connected or when downstream machinery operates under abnormal load conditions.

The circuit breaker’s trip unit monitors the current and evaluates it against configured protection characteristics. If the overload condition exceeds the permitted time-current limits, the breaker initiates a trip operation to disconnect the affected circuit.

This helps reduce the risk of overheating in conductors and electrical equipment.

2. Short-Circuit Protection

A short circuit can produce extremely high current within a very short period. If the fault is not interrupted promptly, it may damage busbars, cables, transformers, switchgear, and connected equipment.

The MasterPact NW circuit breaker is designed to interrupt fault current within its specified breaking-capacity limits.

The actual short-circuit protection performance depends on the selected breaker version, rated voltage, installed trip unit, and system fault level. Engineers must verify that the interrupting capacity is sufficient for the prospective short-circuit current at the installation point.

3. Circuit Isolation and Switching

An air circuit breaker can also provide a controlled means of connecting and disconnecting electrical distribution circuits.

In an industrial switchboard, a main breaker may be used to connect the incoming power supply to the main busbar system. Feeder breakers can then distribute power to individual production areas, motor control centers, or auxiliary electrical panels.

The switching arrangement must follow the manufacturer’s operating instructions and the switchboard’s electrical safety procedures.

4. Trip Unit Monitoring

The installed trip unit determines how the breaker responds to abnormal electrical conditions.

Depending on the specific configuration, protection functions may include long-time overload protection, short-time overcurrent protection, instantaneous short-circuit protection, and ground-fault protection.

Not every NW08 configuration necessarily has the same trip functions. The actual trip-unit model and settings must be identified before protection coordination or replacement work.

5. Fault Interruption and Equipment Protection

When the trip unit identifies a fault condition, the breaker mechanism separates its contacts. The resulting electrical arc is managed by the breaker’s arc-control and interruption system.

This process interrupts the current and isolates the affected circuit, helping limit damage to the electrical installation.

A breaker must always be applied within its specified voltage and interrupting ratings. It should not be assumed to safely interrupt every possible fault current merely because its frame rating is 800 A.

Role in Industrial Power Distribution Systems

The MasterPact NW08N2 can serve as a major protection and switching component in an industrial electrical distribution system.

Main Incoming Circuit Protection

In a main distribution board, an air circuit breaker may be installed between the incoming transformer supply and the main busbar assembly.

Its role is to provide protection and switching for the downstream distribution network. The protection settings must be coordinated with the upstream transformer protection and downstream feeder devices.

Feeder Circuit Protection

Industrial facilities commonly use multiple outgoing feeders to supply different production areas and electrical loads.

A MasterPact NW circuit breaker can be used in a suitable feeder position to protect a distribution circuit supplying motor control centers, production machinery, auxiliary systems, or other switchboards.

The exact rating must be selected according to the feeder load and available fault current.

Busbar Sectionalizing

In some switchboard arrangements, circuit breakers are used to connect or separate sections of a busbar system.

This arrangement can support power distribution flexibility and facilitate maintenance or fault isolation. Whether the NW08N2 is suitable for a particular bus-coupler function depends on its configuration and the switchboard design.

Generator and Transformer Distribution

Low-voltage power distribution systems connected to generators or transformers require appropriately rated protection devices.

A MasterPact NW circuit breaker may be incorporated into such systems when its voltage, current, breaking capacity, and protection characteristics are suitable for the installation.

Protection coordination is particularly important where multiple power sources or parallel operating arrangements are present.

Industrial Applications

The Schneider MasterPact NW series is designed for demanding low-voltage distribution applications. An 800 A frame-class circuit breaker can be considered for appropriately engineered electrical systems.

1. Manufacturing Plants

Manufacturing facilities use electrical distribution systems to supply production machinery, motor control centers, compressors, pumps, and auxiliary equipment.

A suitably configured NW08 circuit breaker can protect an industrial distribution feeder or incoming supply section. It helps isolate electrical faults and supports safe maintenance procedures when used as part of a correctly designed switchboard.

2. Power Distribution Rooms

Main distribution rooms contain switchgear and protective equipment responsible for distributing electrical power throughout a facility.

The NW08N2 can be used in an appropriate low-voltage switchboard to provide high-current circuit protection. Its frame class makes it relevant to systems where feeder current requirements are within the applicable rating limits.

3. Commercial Buildings

Large commercial buildings often require substantial electrical distribution capacity for HVAC systems, elevators, lighting, data infrastructure, and other building services.

An appropriately selected MasterPact NW circuit breaker can be used in a main distribution or feeder protection position.

4. Data Centers

Data centers rely on electrical distribution systems to supply servers, cooling equipment, UPS systems, and supporting infrastructure.

Air circuit breakers may be used in main and secondary distribution assemblies to provide switching and protection. For these applications, engineers must pay particular attention to fault-current calculations, selectivity, redundancy, and maintenance procedures.

5. Infrastructure and Utility Facilities

Water treatment plants, transportation facilities, industrial substations, and other infrastructure installations require reliable low-voltage power distribution.

A MasterPact NW circuit breaker can be incorporated into suitable switchgear assemblies where its electrical and mechanical configuration meets the system requirements.

6. Generator Distribution Systems

Generator distribution systems require circuit protection that accounts for generator characteristics, fault-current contribution, and operating modes.

An NW08 frame-class breaker may be considered for an appropriate distribution position, but the protection settings and interrupting performance must be evaluated against the generator’s technical data and system design.

Installation and System Integration

Correct installation is essential for electrical safety, reliable operation, and long-term service performance.

1. Verify the Exact Breaker Configuration

Before installation, inspect the product nameplate and confirm the complete catalog number.

Important details include:

• Frame rating.
• Rated operational voltage.
• Rated insulation voltage.
• Pole configuration.
• Fixed or drawout mounting arrangement.
• Sensor rating.
• Installed trip-unit type.
• Short-circuit breaking capacity.
• Control and auxiliary accessories.

The NW08 frame designation alone does not provide all the information required for a safe replacement.

2. Confirm Switchboard Dimensions

The supplied dimensions are 352 × 537 × 297 mm.

These dimensions correspond to the manufacturer’s reference dimensions for a fixed-mounted four-pole NW08 configuration. The installation team should confirm the actual dimensions and mounting points against the switchboard drawings.

Adequate space must be provided for electrical connections, mechanical operation, inspection, and maintenance access.

If the breaker is part of a drawout assembly, the cradle and associated switchboard structure must also be checked.

3. Check Electrical Ratings

Verify that the breaker is suitable for the system’s operating voltage, rated current, and prospective short-circuit current.

The 800 A frame rating should not automatically be interpreted as the installed sensor or trip rating. The selected sensor and trip-unit settings must match the actual load and protection requirements.

4. Busbar and Cable Connections

The busbar and cable connections must comply with the manufacturer’s installation requirements.

Check conductor cross-section, connection surfaces, terminal arrangement, tightening torque, phase identification, and electrical clearances.

Incorrect connections may cause overheating, contact resistance, or equipment damage.

5. Protection Coordination

Protection coordination ensures that the circuit breaker closest to a fault can operate without unnecessarily disconnecting a larger section of the electrical system.

Engineers should evaluate the time-current characteristics of the NW08N2 and coordinate them with upstream and downstream protection devices.

The selected settings must also account for cable thermal limits, transformer protection, motor starting conditions, and the installation’s fault-current calculations.

6. Mechanical and Electrical Testing

Before energizing the switchboard, qualified personnel should inspect the breaker mechanism, electrical connections, auxiliary contacts, and control wiring.

Depending on the installation and maintenance requirements, testing may include:

• Mechanical opening and closing checks.
• Trip-unit configuration verification.
• Secondary injection testing.
• Primary injection testing where required.
• Insulation and connection inspections.
• Auxiliary contact and indication checks.
• Verification of interlocks and operating mechanisms.

All testing must follow the manufacturer’s instructions and applicable electrical safety standards.

Compatible System Components

The NW08N2 operates as part of a wider electrical distribution system. The following components may be used alongside an appropriately configured MasterPact NW circuit breaker.

These components are not necessarily included with the NW08N2. Their availability and compatibility depend on the exact breaker configuration.

Alternative Models and Replacement Considerations

The MasterPact NW08 belongs to the 800 A frame class. When selecting an alternative, engineers should compare the electrical characteristics and mechanical configuration rather than relying on the frame designation alone.

Before choosing a replacement, compare:

• Rated operational voltage.
• Frame rating and sensor rating.
• Rated current and trip-unit settings.
• Number of poles.
• Short-circuit breaking capacity.
• Fixed or drawout mounting.
• Terminal and busbar arrangement.
• Auxiliary contact configuration.
• Shunt trip and undervoltage accessories.
• Mechanical dimensions and switchboard compatibility.
• Protection coordination requirements.

A replacement with the same 800 A frame rating may still have a different breaking capacity or mechanical arrangement. Any substitution should be reviewed by qualified electrical engineers.

Key Advantages

High-Current Distribution Capability

The NW08 frame belongs to the 800 A class, making it suitable for appropriately designed low-voltage distribution applications.

Overload and Short-Circuit Protection

With a compatible trip unit and correct settings, the breaker can help protect electrical circuits against overload and short-circuit conditions.

Industrial Switchgear Integration

The MasterPact NW family is designed for integration into low-voltage switchboards and electrical distribution assemblies.

Configurable Protection

Different trip-unit and accessory configurations allow the breaker to be adapted to specific protection and control requirements.

Main and Feeder Circuit Applications

The breaker can be considered for incoming, outgoing, and other distribution positions where its electrical ratings and mechanical configuration are suitable.

Maintenance and Replacement Support

Accurate identification of the model, mounting arrangement, and accessories helps maintenance teams source compatible equipment for existing installations.

Technical FAQs

1. What is the Schneider NW08N2?

The Schneider NW08N2 is identified as a MasterPact NW-series low-voltage air circuit breaker. It is associated with the NW08 800 A frame class and is designed for electrical distribution protection.

2. What is the rated current of the NW08N2?

The NW08 designation corresponds to an 800 A frame rating. The actual sensor rating and protection settings depend on the installed configuration and must be checked on the nameplate.

3. What is the difference between frame rating and trip rating?

The frame rating identifies the breaker frame’s current class. The trip rating is determined by the installed sensor and trip unit. These values may differ, so the frame rating should not be used as the sole basis for system protection calculations.

4. What is the difference between fixed and drawout circuit breakers?

A fixed circuit breaker is mounted directly in the switchboard. A drawout circuit breaker is installed in a compatible cradle and can be moved between operating, test, and disconnected positions according to its design.

The two arrangements have different dimensions and installation requirements.

5. What are the dimensions of the NW08N2?

The supplied listing dimensions are 352 × 537 × 297 mm. These match the reference dimensions for a fixed-mounted four-pole NW08 configuration. Verify the actual unit and mounting arrangement before panel design.

6. What is the weight of the NW08N2?

The supplied weight is 65 kg. This is consistent with the approximate reference weight for a fixed four-pole NW08 configuration.

7. Can the NW08N2 protect a transformer?

It may be used in an appropriately engineered transformer distribution system. The selection must account for transformer rated current, inrush characteristics, available fault current, voltage, and protection coordination.

8. Can this circuit breaker be used as a generator main breaker?

Potentially, provided its electrical ratings, trip characteristics, and interrupting capability are suitable for the generator and distribution system. Generator protection requires specific engineering assessment.

9. What should be checked before purchasing a replacement?

Confirm the complete model number, nameplate data, pole configuration, mounting type, trip unit, sensor rating, breaking capacity, accessories, and physical dimensions. For critical applications, request inspection and functional test information.

10. Can an NW08N2 be replaced by an NW08H2?

Not automatically. Although both belong to the NW08 frame class, their interrupting characteristics and configuration may differ. Verify the system voltage, fault level, trip unit, mounting arrangement, and accessory compatibility before substitution.

Procurement and Maintenance Recommendations

The Schneider NW08N2 is a high-current electrical protection device, so procurement should be based on exact model identification and application requirements.

Before ordering, compare the product nameplate with the installed breaker. Confirm the 800 A frame class, rated voltage, sensor rating, trip-unit type, pole count, breaking capacity, and mounting arrangement.

For used or refurbished equipment, request clear photographs of the nameplate, front panel, terminals, operating mechanism, and accessories. Ask for available inspection or test records, and confirm the product’s physical condition and warranty terms.

The supplied dimensions of 352 × 537 × 297 mm and weight of 65 kg are useful for preliminary product listing and logistics planning. However, actual shipping dimensions and gross weight may differ depending on packaging and included accessories.

Maintenance should follow Schneider Electric’s applicable instructions and the facility’s electrical safety procedures. Qualified personnel should inspect electrical connections, operating mechanisms, auxiliary circuits, and trip-unit settings at appropriate intervals.

Any replacement, adjustment, or testing involving this circuit breaker should be performed by qualified electrical professionals. Incorrect protection settings or incompatible replacement components can affect the safety and selectivity of the entire distribution system.

Conclusion

The Schneider NW08N2 MasterPact NW Circuit Breaker is an 800 A frame-class low-voltage air circuit breaker intended for industrial and commercial electrical distribution systems. It can be used in suitable main distribution, feeder protection, and switchgear applications where its electrical and mechanical configuration meets the system requirements.

The supplied dimensions of 352 × 537 × 297 mm and weight of 65 kg correspond to the reference values for a fixed four-pole NW08 configuration. Before installation or replacement, engineers should verify the complete breaker designation, trip unit, sensor rating, voltage, breaking capacity, pole configuration, and mounting arrangement.

Accurate model verification and professional installation are essential for maintaining reliable electrical protection and safe operation in industrial power distribution systems.