3VA5212-5EC31-0AA0 - MFAS 125 Amp Circuit Breaker

3VA5212-5EC31-0AA0 - MFAS 125 Amp Circuit Breaker

The Siemens 3VA5212-5EC31-0AA0 is one of those breakers that does what it’s supposed to do—no extra fluff, no complicated setup. It’s a 125-amp, 3-pole unit from the 3VA5 line, built for everyday commercial and light industrial use where reliability matters more than bells and whistles. It uses a thermal-magnetic trip, so you’re covered on both overloads and short circuits. The settings are fixed—125A for overload, and instantaneous Trip at 10x the rated current—so there’s nothing to tweak or second-guess during install. That’s usually a plus if you want to get the job done and move on. With a 35kA rating at 480V, it’s a solid choice for systems where available fault current isn’t low. It’s not oversized, but it’s got enough capacity to handle tougher conditions without being pushed to the limit. Physically, it's a 250 frame, so it’s compact enough for most panels without feeling cramped. If you’ve worked with Siemens 3VA breakers before, this will feel familiar right out of the box.

Key Features and Benefits

• 125 Amp Rating – Works well for a wide range of standard applications
• 3-Pole Breaker – Full three-phase protection
• 35kA @ 480V – Suitable for higher fault current environments
• Thermal-Magnetic Trip – Simple, proven protection style
• Fixed Settings – No adjustments, less room for setup mistakes
• Instantaneous Trip at 10x – Fast reaction during faults
• 3VA52 Frame (250 Frame) – Good balance of size and capability

Technical Specifications

• Manufacturer: Siemens
  
• Part Number: 3VA5212-5EC31-0AA0
  
• Series: 3VA52 / 3VA5
  
• Poles: 3
  
• Amperage: 125A
  
• Voltage: Up to 480V
  
• Interrupting Rating: 35kA @ 480V
  
• Trip Type: Thermal Magnetic (TM230)
  
• Overload Protection: 125A (fixed)
  
• Instantaneous Trip: 10 × In
  
• Frame Size: 250
  
• Dimensions: 9.65" H × 6.3" W × 5.9" D
  

Material Compliance and Certifications

• Industry Standards: This breaker is part of Siemens’ UL-listed 3VA5 series, meeting North American safety and performance standards. It’s built for consistent, long-term operation—nothing experimental, just established protection hardware widely used in the field.
  

Where It Works Best

• Commercial panels and building systems
• Light industrial equipment
• Manufacturing setups with moderate fault levels
• Replacement jobs where a Siemens 3VA breaker is already in place
• General three-phase distribution