ET4039 - 90Amp Circuit Breaker

ET4039 - 90 Amp Circuit Breaker

When you're dealing with an existing electrical setup, the last thing you want is guesswork. The ET4039 molded case circuit breaker is built for exactly that situation—giving you a reliable, no-surprises replacement that fits and functions the way your system expects. This 90-amp, 3-pole breaker is designed for three-phase power distribution and provides the level of protection you need against overloads and short circuits. With a 14kA interrupting rating at 480VAC, it's suited for systems where that capacity is required to safely manage fault conditions. The F frame size matters here—it helps ensure the breaker seats correctly in compatible panelboards, avoiding the headaches that come with mismatched components. It's also rated for 40°C environments, which means it handles the everyday conditions found in most commercial and industrial electrical rooms without issue. No overpromises—just a solid, dependable breaker that does its job and keeps your system protected.

Key Features and Benefits

• Built for 90 amp applications in commercial and industrial systems
• 3-pole design supports standard three-phase power distribution
• 14kA interrupting capacity at 480VAC for handling fault events safely
• F-frame construction ensures a proper fit in compatible equipment
• Molded case enclosure helps protect internal components from damage
• Designed for 40°C operating conditions commonly found in the field
• Made to last with consistent, predictable performance

Technical Specifications

• Part Number: ET4039
  
• Amperage: 90A
  
• Poles: 3
  
• Voltage Rating: 480VAC
  
• Interrupting Capacity: 14kA @ 480VAC
  
• Frame Type: F
  
• Temperature Rating: 40°C
  
• Breaker Type: Molded Case Circuit Breaker
  
• Shipping Weight: 4.5 lbs
  
• Height: 10.0 inches
  

Material Compliance and Certifications

• Meets standard industry expectations for circuit protection devices
• Suitable for installations aligned with the NEC (National Electrical Code)
• Constructed using typical molded case insulating materials
• Tested for proper performance within its rated interrupting capacity

Where It Works Best

• The ET4039 is a strong fit for facilities that rely on existing three-phase distribution systems—think commercial buildings, manufacturing spaces, and service panels where compatibility matters. It's commonly used for HVAC systems, motor loads, and general power distribution circuits. If you're replacing a breaker and need it to match what's already in place, this one keeps things simple and straightforward.