NGB3B125B - 125 Amp Circuit Breaker

NGB3B125B - 125 Amp Circuit Breaker

Upgrade your electrical protection with the Siemens NGB3B125B, a high-performance 3‑pole, 125 A circuit breaker designed for low-voltage panelboard installations. Built to handle demanding loads and fault currents, this breaker delivers dependable thermal‑magnetic protection for a wide range of electrical systems. Whether you’re outfitting an industrial plant, a commercial facility, or a heavy-duty residential panel, the NGB3B125B brings peace of mind by helping prevent overloads and short circuits — keeping equipment safe and operations running without interruption.

Key Features and Benefits

• Thermal‑Magnetic Trip Unit: Offers dependable overload and short‑circuit protection, automatically switching off power when necessary to prevent damage.
• High Interrupting Capacity: With a breaking capacity of 14 kAIC at 600Y/347 V AC and 25 kAIC at 480Y/277 V AC, this breaker is capable of safely interrupting high fault currents in demanding environments.
• Compact, Space‑Saving Design: Measuring approximately 3" wide, 5.4" high, and 2.8" deep, it fits easily into panelboards with limited space, making installation and maintenance simpler.
• Load-Side Lugs Only: Streamlines installation and reduces clutter by accepting wire sizes from 8 AWG up to 1/0 AWG (copper or aluminum), ideal for systems with heavy wiring requirements.

Technical Specifications

• Amperage: 125 A
  
• Poles: 3
  
• Voltage Rating: 600Y/347 V AC; 480Y/277 V AC
  
• Interrupting Capacity:
  • 14 kAIC at 600Y/347 V AC
  • 25 kAIC at 480Y/277 V AC
• Dimensions:
  • Width: 3.0 inches
  • Height: 5.4 inches
  • Depth: 2.8 inches
• Weight: 2.615 lbs
  
• Wire Range: 8 AWG to 1/0 AWG (Copper or Aluminum)
  

Material Compliance and Certifications

• UL Listed: Meets rigorous safety and quality standards established by Underwriters Laboratories.
• RoHS Compliant: Free from restricted hazardous substances in line with the Restriction of Hazardous Substances directive.
• WEEE Compliant: Designed and manufactured in compliance with electronic waste and recycling regulations, supporting responsible disposal and environmental stewardship.

Where It Works Best

• The Siemens NGB3B125B is an excellent choice for industrial machinery panels, commercial distribution boards, and heavy-load residential or mixed-use installations. It’s particularly well-suited for environments where high fault-current capacity and reliable, automatic protection are critical — such as manufacturing floors, HVAC systems, large-scale lighting or power distribution systems, and other high-demand electrical applications. Whether you’re an electrical contractor, facility manager, or design engineer, this breaker gives you dependable protection and performance to keep your systems safe and operational.