Siemens NEB3B040B - 40 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

The Siemens NEB3B040B is a rugged 40A, 600V, 3-pole bolt-on molded case circuit breaker designed to safeguard distribution panels with precision and confidence. Built for dependable branch circuit overcurrent and short-circuit protection, this unit is purpose‑built for consistent performance in panelboards and loadcenters across residential, commercial, and light industrial environments.

• Secure bolt-on mounting: A rigid, vibration-resistant bus connection that stays tight through operation, vibration, and routine panel movements—minimizing the risk of loose connections and intermittent trips.
• Thermal-magnetic trip unit: Combines thermal and magnetic protection to deliver stable, repeatable trip characteristics across a wide range of loads and temperatures, reducing nuisance tripping and ensuring reliable protection when it matters most.
• 3-pole, 40A, 600V design: Suitable for 3-phase distribution in small to mid-size installations, ideal for protecting motor starts, lighting circuits, and other branch circuits in both commercial spaces and light industrial setups.
• OEM panel compatibility: Specifically engineered to pair with Siemens OEM loadcenters and panelboards, ensuring a seamless fit, consistent mounting geometry, and aligned trip curves for coordinated protection.
• Versatile applications: From retrofit projects in existing panelrooms to new installations in service panels, this breaker delivers reliable protection for multiple circuit types within a single, compact unit.

Why choose the Siemens NEB3B040B? It isn’t just about rating—it's about dependable protection that remains consistent under real-world conditions. The bolt-on installation provides a sturdier bus connection than plug-on alternatives, especially in panels subject to vibration or movement. The integrated thermal-magnetic trip mechanism responds quickly to short circuits while smoothing out temperature-related drifts, helping you maintain safe, protected electrical systems with fewer interruptions.

Technical snapshot

• Manufacturer: Siemens
• Part Number: NEB3B040B
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 40A
• Voltage Rating: 600V
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Whether you’re upgrading a panel to handle higher demand, wiring a new 3-phase distribution layout, or replacing an aging breaker in a Siemens system, the NEB3B040B offers precise protection, dependable mounting, and seamless compatibility with Siemens loadcenters. It’s a practical, efficient choice for reliable electrical distribution in the spaces that keep your operations running smoothly.