Siemens B345HH - 45 A, 240 V, 3-Pole Bolt-On Circuit Breaker | AmpState

The Siemens B345HH is a 45A, 240V, 3-pole bolt-on molded case circuit breaker designed to protect your electrical system with precision and reliability. Built for dependable branch circuit overcurrent and short-circuit protection, it integrates smoothly into panelboards and load centers used in residential, commercial, and light industrial settings.

Why this breaker stands out

• Secure bolt-on mounting—a rigid, vibration-resistant bus connection that stays tight through equipment starts and shutdowns, reducing the risk of loose connections over time.
• Thermal-magnetic trip unit—delivers stable, repeatable protection performance across a wide range of loads and fault conditions, helping to prevent nuisance tripping while still safeguarding circuits.
• OEM-compatible design—works with matching Siemens OEM load centers and panelboards for straightforward installation and dependable system integration.
• Versatile, three-pole protection—ideal for three-phase distribution in residential, commercial, and light industrial environments, where reliable phase protection is essential.

Key technical specifications

• Manufacturer: Siemens
• Part Number: B345HH
• 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

Practical use cases

Whether you’re upgrading an aging panel or specifying a new installation, the B345HH provides robust protection for three-phase circuits. It’s well-suited for:

• Residential subpanels feeding critical electrical rooms or heat pumps where three-phase protection is required
• Commercial service entrance panels and small to mid-size load centers
• Light industrial equipment circuits where reliable trip performance under fault conditions is essential

How it helps your project

Choosing a bolt-on molded case breaker like the B345HH delivers a compelling combination of mechanical durability and electrical protection. The bolt-on interface creates a solid mechanical connection that resists vibration, while the thermal-magnetic trip unit provides fast, predictable responses to overloads and short circuits. Coupled with OEM panel compatibility, this breaker minimizes installation surprises and simplifies maintenance over the life of the system.

Installation and integration tips

• Pair with Siemens OEM load centers and panelboards to ensure optimal fit and coordinated protection schemes.
• Verify three-phase circuit requirements and ensure the 240 V rating aligns with your distribution setup.
• Mount securely in a compatible panelboard using the bolt-on method to maintain a stable electrical path and reduce vibration-induced wear.