3VA5212-7EF31-0AA0 - CFAS 125 Amp Circuit Breaker

3VA5212-7EF31-0AA0 - CFAS 125 Amp Circuit Breaker

If you’ve worked around electrical systems for any length of time, you know not all breakers are created equal. The Siemens 3VA5212-7EF31-0AA0 is the kind you install when you want it done right the first time. This is a 125-amp, 3-pole breaker built on Siemens’ 3VA5 platform, and it’s designed for real-world conditions—not just specs on paper. With a 100kA interrupting rating at 480V, it’s ready for high fault current situations where fewer breakers aren’t enough. It uses a thermal magnetic trip unit, which most pros prefer for its reliability and straightforward operation. Overload protection is set to 125 amps, and the instantaneous trip is set to 10 times the rated current. In other words, it reacts fast when there’s a problem, without needing constant adjustments or fine-tuning. It’s also compact for its class, which makes a difference when panel space is tight. Whether you’re replacing an existing unit or building out a new system, this breaker fits in without creating headaches.

Key Features and Benefits

• 100kA interrupting rating @ 480V: handles high fault current with confidence
• 125 amp rating: a go-to size for many commercial and industrial setups
• Thermal magnetic trip: simple, proven protection that works
• Fixed overload setting: no adjustments, no surprises
• Instantaneous trip at 10x In: quick response to short circuits
• 3-pole configuration: designed for three-phase systems
• Compact 250 frame design: easier installs in tighter panels
• C-class (CFAS): built for more demanding applications

Technical Specifications

• Manufacturer: Siemens
  
• Part Number: 3VA5212-7EF31-0AA0
  
• Series: 3VA52 / 3VA5 Frame 250
  
• Poles: 3
  
• Amperage: 125A
  
• Interrupting Rating: 100kA @ 480V
  
• Trip Unit: Thermal Magnetic (TM240, ATAM)
  
• Overload Protection (Ir): 125A (fixed)
  
• Short-Circuit Protection (Ii): 10 × In
  
• Dimensions:
  • 9.65" H × 6.3" W × 5.9" D

Material Compliance and Certifications

• UL Listed: for use in U.S. electrical systems
• IEC Alignment: Designed to align with IEC standards
• RoHS compliant: for reduced hazardous materials
• Application Suitability: Suitable for applications where safety and code compliance are critical
  

Where It Works Best

• You’ll typically see this breaker used in: Commercial buildings and office spaces Industrial panels and equipment protection Manufacturing facilities Data centers and critical power systems Retrofit or replacement projects using Siemens gear