THJK426300 - 300Amp Circuit Breaker

THJK426300 - 300 Amp Circuit Breaker

The THJK426300 circuit breaker is a 2-pole, 300-amp molded-case circuit breaker designed for use in your commercial and industrial electrical distribution systems that require dependable overcurrent and short-circuit protection. As part of the THJK4 series, this breaker features a thermal-magnetic trip unit, an internal common trip, and a non-interchangeable trip design, helping to provide consistent protection for connected equipment and conductors. Built for long service life, the THJK426300 is a bolt-on Q-Line circuit breaker that includes load-side lugs for installation convenience and secure conductor termination.

With interrupting ratings of 25kA at 600VAC, 35kA at 480VAC, and 65kA at 240VAC, the THJK426300 is well-suited for applications where higher fault current levels may be present. Its HACR rating makes it suitable for heating, air conditioning, and refrigeration equipment applications when installed in accordance with applicable electrical codes and equipment requirements. Designed to match the original form, fit, and function of compatible systems, this breaker serves as a practical solution for maintaining existing electrical infrastructure while helping you to protect critical equipment from electrical faults.

Key Features and Benefits

• 300 Amp Current Rating: 300 Amp current rating for high-capacity power distribution applications.
• 2-Pole Configuration: 2-pole configuration for protecting two energized conductors.
• THJK4 Molded Case Design: Type THJK4 molded case circuit breaker design.
• Thermal Magnetic Protection: The thermal magnetic trip unit provides both overload and short-circuit protection.
• Internal Common Trip: The internal common trip mechanism helps ensure the simultaneous tripping of all poles during fault conditions.
• Bolt-On Mounting: Bolt-on mounting configuration for secure installation.
• Q-Line Compatible: Q-Line compatible design.
• HACR Rated: HACR rated for qualifying heating, air conditioning, and refrigeration equipment applications.
• Load-Side Lugs Included: Includes load-side lugs for conductor termination.
• Long-Term Durability: Designed for long-term durability and dependable operation.
• Commercial and Industrial Applications: Suitable for commercial, industrial, and large electrical distribution systems.
  

Technical Specifications

• Part Number: THJK426300
  
• Type: THJK4
  
• Circuit Breaker Style: Molded Case Circuit Breaker
  
• Mounting: Bolt-On
  
• Series: Q-Line
  
• Poles: 2
  
• Amperage: 300A
  
• Trip Unit: Non-Interchangeable Thermal Magnetic
  
• Trip Configuration: Internal Common Trip
  
• A.I.C. Rating:
  • 25kA @ 600VAC
  • 35kA @ 480VAC
  • 65kA @ 240VAC
• HACR Rated: Yes
  
• Included Accessories: Load-Side Lugs
  
• Dimensions:
  • Height: 10.13 in.
  • Width: 8.25 in.
  • Depth: 3.81 in.

Material Compliance and Certifications

• HACR Rated: HACR Rated for qualifying HVAC and refrigeration applications.
• Industry Standards: Manufactured and tested to applicable industry standards for molded case circuit breakers.
• Code Compliance: Designed for installation and use in accordance with the National Electrical Code (NEC) and applicable local electrical regulations.
• Equipment Compatibility: Suitable for use within properly rated and compatible electrical distribution equipment.
  

Where It Works Best

• The THJK426300 is commonly used in commercial buildings, industrial facilities, manufacturing operations, distribution equipment, mechanical systems, and large electrical service applications requiring a 300-amp, 2-pole circuit breaker. It is particularly well-suited for electrical systems utilizing compatible Q-Line equipment and for installations where a bolt-on molded-case circuit breaker with thermal-magnetic protection and HACR suitability is required. Its form, fit, and functional compatibility make it a practical choice for maintaining existing electrical systems while helping ensure continued protection of connected equipment and circuits.