Siemens BQ3B045H - 45 A, 240 V, 3-Pole Bolt-On Circuit Breaker | AmpState

The Siemens BQ3B045H is a 45A, 240V, 3-pole bolt-on molded case circuit breaker designed to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and loadcenters. Built for durability, this unit features a secure bolt-on mounting that creates a rigid, vibration-resistant bus connection, helping you maintain consistent electrical performance even in demanding environments.

Key to its reliability is the thermal-magnetic trip system. The thermal element handles gradual overloads with precision, while the magnetic component delivers fast, decisive disconnection during short-circuit events. Together, they provide stable, repeatable protection you can trust for sensitive equipment and essential loads.

What sets the BQ3B045H apart

• Secure bolt-on mounting ensures a rigid bus connection and reduces vibration-related wear in panelboards and loadcenters.
• Thermal-magnetic trip unit delivers coordinated protection: smooth endurance during normal operation and immediate interruption when faults occur.
• 3-pole, 45A, 240V configuration ideal for three-phase circuits and mid-range protection in commercial or light industrial applications.
• OEM-compatible design works with matching Siemens OEM load centers and panelboards for seamless integration.
• Versatile applications suitable for residential, commercial, and light industrial settings where reliable branch-circuit protection is essential.

Technical snapshot

• Manufacturer: Siemens
• Part Number: BQ3B045H
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 45 A
• Voltage Rating: 240 V
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Designed for installers who value reliability and straightforward integration, the BQ3B045H simplifies panel upgrades and new installations alike. Whether you're protecting a 3-phase motor circuit, safeguarding critical HVAC equipment, or adding a dependable main or sub-feed breaker to a Siemens panel, this unit delivers consistent performance. Its rugged bolt-on design keeps connections solid even in environments with vibration or limited maintenance, while the thermal-magnetic protection adapts to varying load conditions without nuisance trips.

Practical tips for use: verify that your panel is compatible with bolt-on molded case breakers of this type, ensure correct torque and mounting per your panel’s guidelines, and pair with other Siemens components to maintain a coherent protection strategy across your distribution system. The BQ3B045H is a purpose-built choice when you need robust, predictable protection for 45 amps at 240 volts in residential, commercial, or light industrial projects.