Siemens B345 - 45 A, 240 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Experience dependable branch circuit protection with the Siemens B345 — a 45A, 240V, 3-pole bolt-on molded case circuit breaker designed for panelboards and loadcenters. Engineered for durability, it delivers reliable overcurrent and short-circuit protection in residential, commercial, and light industrial settings. Available from AmpState, this breaker is built to integrate seamlessly with your existing Siemens infrastructure.

Why the Siemens B345 stands out

• Secure bolt-on mounting: The bolt-on design creates a rigid, vibration-resistant bus connection, reducing movement and ensuring consistent electrical performance in challenging environments.
• Thermal-magnetic trip unit: Combines thermal overload protection with magnetic short-circuit protection for stable, repeatable performance across varying temperatures and loads.
• OEM compatibility: Specifically engineered to be compatible with matching Siemens loadcenters and panelboards, ensuring a clean, reliable fit without adapters or improvisation.
• Versatile application: Suitable for a range of settings—from home panels to commercial spaces and light industrial distribution—where dependable protection is essential.

Technical snapshot

• Part number: B345
• Amperage: 45A
• Voltage: 240V
• Poles: 3
• Mounting style: Bolt-on
• Type: Thermal-magnetic molded case circuit breaker
• Application: Branch circuit overcurrent and short-circuit protection

Practical use cases

Install the B345 in residential main distribution panels to guard lighting and receptacle circuits, or use in commercial spaces to protect feeders and critical equipment. Its robust bolt-on construction makes it ideal for panels in environments with vibrations or movement, such as workshops, maintenance rooms, or outdoor-rated enclosures with frequent door closures. For light industrial setups, it provides dependable protection for small machinery circuits, HVAC controls, and power distribution routes.

How it helps you decide

If you value a protection solution that stays in place under stress and delivers consistent trip performance, the B345 delivers. The thermal-magnetic trip unit reduces nuisance trips from transient temperature changes, while the bolt-on design ensures a solid electrical connection over time. When pairing with Siemens OEM panelboards and loadcenters, you gain a cohesive, predictable protective system rather than a mismatched add-on.

Who benefits most

• Electrical contractors and installers seeking a reliable, plug-critical component for Siemens-based panels
• Facility managers overseeing residential buildings, offices, retail spaces, and light industrial equipment
• Maintenance professionals targeting consistent protection for critical circuits

Elevate your electrical protection with the Siemens B345 45A 240V 3-Pole Bolt-On Circuit Breaker — a purpose-built solution for durable, precise overcurrent and short-circuit protection. Add it to your AmpState cart today to ensure your panelboards and loadcenters operate with trusted Siemens performance.