Square D QOB340 - 40 A, 240 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D QOB340 from AmpState—a 40A, 240V, three-pole bolt-on molded case circuit breaker designed to protect panelboards and load centers from overcurrent and short circuits. Built for durability and consistent performance, this breaker integrates smoothly with OEM installations for dependable, long‑lasting distribution protection.

Why this QOB340 stands out

• Secure bolt-on mounting provides a rigid, vibration-resistant bus connection, helping maintain a reliable, tight electrical path even in noisy or demanding environments.
• Thermal-magnetic trip unit delivers stable, repeatable protection—responding quickly to short circuits and preventing nuisance trips while guarding connected equipment.
• OEM-compatible design ensures a seamless fit with matching Square D load centers and panelboards, making replacements and upgrades straightforward and risk-free.
• Versatile application ideal for residential, commercial, and light industrial settings, where dependable 40A, 240V protection supports a wide range of feeders and circuits.

Technical specifications

• Manufacturer: Square D
• Part Number: QOB340
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 40A
• Voltage Rating: 240V
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Ideal for

• Panels and load centers requiring a 3-pole, 40A device for 240V circuits
• Replacements or upgrades in OEM Square D installations to maintain compatibility and performance
• Residential, commercial, and light industrial environments where durable, dependable protection matters

Practical use cases and guidance

The QOB340 is crafted for bolt-on installation in compatible panelboards, making it a practical choice for field upgrades and new builds alike. In environments with vibration—such as near HVAC equipment or other heavy machinery—the bolt-on design helps preserve a solid connection, reducing the risk of loosening over time. Use this 3-pole breaker to guard 3-wire 240V feeders or suitable three-phase loads in appropriate Square D panels.

With its rugged molded-case construction and thermally assisted protection, this breaker balances durability with precise response. Pair it with matching OEM components to maintain a cohesive, reliable electrical distribution system that stands up to everyday use.

Ready to safeguard your electrical distribution? Add the Square D QOB340 40A/240V/3-Pole Bolt-On Circuit Breaker from AmpState to your cart and experience dependable protection designed to endure and perform.