999340 - 40 Amp Circuit Breaker

999340 - 40 Amp Circuit Breaker

If you’re replacing a breaker in an existing setup, you already know the job isn’t about “finding something close.” It has to match. The 999340 molded case circuit breaker is built for that exact purpose—a 40-amp, 3-pole breaker designed for systems running up to 600VAC, with an ML-1 (F-frame) that matches the equipment it was originally installed in. This is a thermal-magnetic breaker, so it reacts the way you’d expect: it handles overloads over time and trips fast when there’s a short circuit. No surprises, no unnecessary adjustments—just consistent protection for the equipment it’s connected to. The molded case design keeps everything contained and protected, and the overall build reflects what these breakers were made for: staying in service for the long haul. When you’re maintaining or repairing an existing panel, that’s exactly what matters.

Key Features and Benefits

• 40 Amp rating for standard load protection
• 3 poles for use in three-phase systems
• Thermal-magnetic trip for both overload and short-circuit protection
• 600VAC rating for higher-voltage applications
• ML-1 (F-frame) ensures proper fit in compatible equipment
• Molded case construction helps protect internal components
• Compact size makes installation straightforward in existing panels

Technical Specifications

• Part Number: 999340
  
• Amperage: 40A
  
• Poles: 3
  
• Voltage Rating: 600VAC
  
• Frame Type: ML-1 (F-Frame)
  
• Trip Type: Thermal-Magnetic
  
• Dimensions:
  • 4.50" W x 6.50" L x 3.00" D
• Shipping Weight: 7 lbs
  

Material Compliance and Certifications

• Industry Standards: Manufactured from standard materials commonly used in molded-case circuit breakers, this unit is intended for installation in systems designed to meet applicable electrical codes. Always verify compatibility with your specific equipment and local code requirements.
• UL Standards: When installed according to electrical codes, you can have confidence that this unit adheres to expected construction and compliance benchmarks.
  

Where It Works Best

• Existing commercial and industrial electrical panels
• Three-phase distribution systems
• Maintenance and repair jobs where specs must match
• Equipment protection in 600VAC environments
• Any setup requiring an ML-1 frame breaker