Abb XT5NU340ABFF000XXX 400A 3P Molded Case Circuit Breaker

Product Description

The ABB XT5NU340ABFF000XXX is a molded case circuit breaker from the TMAX XT5N series, rated at 400 amps with a three-pole, fixed-mount configuration. It is equipped with a thermomagnetic TMA release, providing both thermal overload protection and magnetic short-circuit protection in a single device. The magnetic trip range is set at 2000 to 4000 amps, supporting adjustable instantaneous tripping for coordinated system protection. Front terminals are integrated into the fixed frame design. The breaker carries UL and CSA listings and features a fully rated neutral, making it suitable for four-wire electrical distribution systems where neutral integrity is required.

This circuit breaker is designed for use in commercial and industrial power distribution panels, switchboards, and motor control centers. Its fixed mounting configuration suits installations where drawout capability is not required. Electricians and electrical contractors working on branch circuit or feeder applications will find this breaker appropriate for load centers operating under NEC-governed distribution designs. The fully rated neutral is particularly relevant in installations with high harmonic content or unbalanced loads where neutral derating is not acceptable.

Key Features

• 400-amp continuous current rating with thermomagnetic TMA release
• Magnetic short-circuit trip range: 2000 to 4000 amps (I3 adjustable)
• Three-pole, fixed-mount construction with front terminal connections
• Fully rated neutral for four-wire distribution applications
• UL and CSA listed for North American installations
• TMAX XT5N series platform for coordinated protective device applications

Compatibility

Designed as a fixed-mount molded case circuit breaker for use in commercial and industrial distribution equipment rated for 400-amp feeder or branch circuit applications per applicable UL and CSA standards.

Installation Notes

Installation must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and any applicable local codes. De-energize and lock out the upstream supply before handling or connecting this breaker. Front terminal connections require proper torque and conductor sizing per the breaker's published termination requirements. Verify that the enclosure or switchboard is rated to accept the XT5N fixed-mount frame before installation.

Technical Specifications

• Series: TMAX XT5N
• Current Rating: 400 amps
• Number of Poles: 3
• Release Type: Thermomagnetic TMA
• Magnetic Trip Range (I3): 2000 to 4000 amps
• Mounting Style: Fixed
• Terminal Type: Front terminals
• Neutral Rating: Fully rated neutral
• Listings: UL, CSA

Standard Information

• Brand: ABB
• Manufacturer Part Number: XT5NU340ABFF000XXX