DK3400Y - 400Amp Circuit Breaker

DK3400Y - 400Amp Circuit Breaker

The DK3400Y is a 400 Amp three-pole molded case circuit breaker from Eaton's trusted Series C product line. It's commonly found in commercial and industrial power distribution systems where dependable protection and high-current capacity are essential. When an existing DK-frame breaker needs replacement, matching the original catalog number helps maintain the panel's intended design, electrical ratings, and physical fit.

In many facilities, this breaker serves as a main, feeder, or large branch circuit protective device. Its three-pole configuration allows all phases to disconnect simultaneously, making it well suited for protecting three-phase equipment, distribution panels, motor loads, and other critical electrical systems.

One feature that makes the DK3400Y especially useful in certain applications is its built-in 12–24 VAC/DC shunt trip. This allows the breaker to be opened remotely when connected to an external control circuit. You'll often find this functionality used in emergency shutdown systems, safety circuits, and installations that require remote breaker operation.

Key Features and Benefits

• 400 Amp molded case circuit breaker for commercial and industrial power systems
• Three-pole design for three-phase circuit protection
• Eaton Series C DK-frame complete breaker assembly
• T186 trip unit for overload and short-circuit protection
• Rated for 240 VAC and 250 VDC applications
• 65kAIC interrupting rating at 240 VAC
• 10kAIC interrupting rating at 250 VDC
• Rear-mounted 12–24 VAC/DC shunt trip with left pigtail connection
• Line-side terminal configuration
• Designed for use in existing DK-frame installations
• Helps maintain original equipment fit and electrical specifications
• Built to provide long-lasting service in demanding electrical environments

Technical Specifications

• Catalog Number: DK3400Y
  
• Manufacturer: Eaton
  
• Series: Series C
  
• Product Type: Molded Case Circuit Breaker
  
• Circuit Breaker Type: DK
  
• Frame Type: Complete Breaker
  
• Frame Size: K Frame
  
• Amperage Rating: 400 Amps
  
• Voltage Rating: 240 VAC, 250 VDC
  
• Frequency Rating: 50/60 Hz
  
• Number of Poles: 3
  
• Trip Type: T186
  
• Interrupt Rating: 65 kAIC at 240 VAC
  
• Interrupt Rating (DC): 10 kAIC at 250 VDC
  
• Shunt Trip: 12–24 VAC/DC Rear-Mounted with Left Pigtail
  
• Terminals: Line Side
  
• Length: 4.1 Inches
  
• Width: 5.5 Inches
  
• Height: 5.5 Inches
  
• Weight: 11.5 lb
  

Material Compliance and Certifications

• UL Listed: The DK3400Y is UL Listed and manufactured to meet applicable industry standards for molded case circuit breakers.
• Professional Installation: It is intended for installation and service by qualified electrical professionals in accordance with local, state, and national electrical codes.
• Application Verification: Proper application should always be verified against system requirements, available fault current, and equipment specifications.
  

Where It Works Best

• Commercial electrical distribution systems
• Industrial power distribution equipment
• Switchboards and switchgear assemblies
• Main, feeder, and large branch circuit applications
• Three-phase power systems
• Facilities requiring remote shunt trip capability
• Emergency shutdown and safety control systems
• Maintenance and replacement projects using Eaton DK-frame breakers
• Applications requiring a 400 Amp three-pole molded case circuit breaker
• Existing Eaton Series C installations where matching form, fit, and function is important