Technical Review: Mitsubishi Electric NF50-FAU 2P 50A Molded Case Circuit Breaker - Selection Guide & Specs
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Overview
The Mitsubishi Electric NF50-FAU 2P 50A Molded Case Circuit Breaker addresses critical industrial electrical protection challenges by providing reliable overcurrent and short-circuit protection for medium-power applications. This compact yet robust device prevents catastrophic equipment failure and electrical fires by automatically interrupting fault currents before they can cause damage to motors, transformers, and distribution systems.
Technical Specifications
| Parameter | Specification |
|---|---|
| Rated Current | 50A |
| Number of Poles | 2P (2-pole) |
| Rated Voltage | 400V AC (IEC 60947) |
| Short Circuit Breaking Capacity (Icu) | 1.5kA at 400V AC |
| Frame Size | NF50 |
| Protection Type | Thermal-magnetic (combined overload and short-circuit) |
| Mounting | DIN rail (35mm) |
| Standards Compliance | UL 489, IEC 60947-2 |
| Dimensions (W x H x D) | 54mm x 78mm x 70mm (approx.) |
| Operating Temperature | -25°C to +55°C |
Application Analysis
The NF50-FAU excels in protecting industrial motor circuits, lighting distribution panels, and small power distribution systems. Its thermal-magnetic protection mechanism provides dual-layer security: the thermal element guards against sustained overload conditions that could damage motor windings, while the magnetic element responds instantly to short-circuit faults. This makes it ideal for applications requiring reliable protection for motor control centers and distribution panels.
Buying Considerations
When selecting the Mitsubishi Electric NF50-FAU 2P 50A circuit breaker, consider these critical factors:
Current Rating Matching: Ensure the 50A rating matches your load requirements. For motor circuits, consider starting current and duty cycle. The thermal element is calibrated for continuous 50A operation with appropriate derating for ambient temperature.
Breaking Capacity Verification: The 1.5kA short-circuit breaking capacity must exceed your system's maximum available fault current. For higher fault current applications, consider higher-rated MCCBs from the NF series.
Voltage Compatibility: Verify your system voltage matches the 400V AC rating. For different voltage requirements, explore alternative models in the Mitsubishi MCCB range.
Pole Configuration: The 2-pole design is ideal for single-phase or split-phase systems. For three-phase applications, consider the 3-pole NF50-FAU variant.
Installation Environment: Ensure proper ventilation and ambient temperature conditions within the specified -25°C to +55°C range for optimal performance.
Frequently Asked Questions
Q: Can the NF50-FAU be used for motor protection applications?
A: Yes, the thermal-magnetic protection is well-suited for motor circuits. The thermal element protects against overload conditions during motor starting and operation, while the magnetic element provides instantaneous protection against short-circuit faults.
Q: What is the difference between Icu and Ics ratings in this circuit breaker?
A: Icu (Ultimate Breaking Capacity) is the maximum fault current the breaker can interrupt once without repair. Ics (Service Breaking Capacity) is the current it can interrupt multiple times while remaining operational. The NF50-FAU has an Icu rating of 1.5kA at 400V AC.
Q: Is this circuit breaker suitable for residential applications?
A: While technically capable, the NF50-FAU is primarily designed for industrial and commercial applications. For residential use, consider residential-grade circuit breakers that meet specific household electrical standards.
