Square D QOB340GFI - 40 A, 240 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D QOB340GFI from AmpState — a 40A, 240V, 3-pole bolt-on molded‑case circuit breaker designed to protect your panelboards and load centers with dependable, consistent performance. Built for real-world installations, this unit pairs robust construction with precise protection to keep your electrical system running smoothly.

Why technicians choose this breaker

• Secure bolt-on mounting: delivers a rigid, vibration‑resistant bus connection that stays tight through busy panels and routine service.
• Thermal-magnetic trip unit: provides stable, repeatable protection by combining a thermal element for overloads with a magnetic element for fast short-circuit response.
• OEM compatibility: designed to integrate seamlessly with matching Square D panels, ensuring predictable fit and coordinated protection in your loadcenter.
• Versatile applications: suitable for residential, commercial, and light industrial environments where reliable 240V, 3-pole protection is required.

Technical snapshot

• Manufacturer: Square D
• Part number: QOB340GFI
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 40 A
• Voltage rating: 240 V
• Number of poles: 3
• Mounting style: Bolt-on
• Applications: Branch circuit overcurrent and short-circuit protection

Practical use cases and installation tips

Ideal for 3-pole 240V circuits in panelboards and load centers, including commercial panels, subpanels, and certain industrial applications. When upgrading an existing installation or expanding a distribution group, pair this breaker with the appropriate OEM Square D panels to ensure proper fit and protection coordination. For installation, follow the manufacturer’s torque guidelines to maintain a solid bus connection and reliable trip performance.

What problems this solves

With a secure bolt-on design and a well-behaved thermal-magnetic trip, the QOB340GFI minimizes nuisance trips and sustains protection under varying loads and conditions. Its rigid mounting helps resist connection loosening in vibration-prone environments, delivering dependable branch circuit protection where it matters most.

Who this is ideal for

• Homeowners or electricians upgrading residential panelboards that require 240V, 3-pole protection
• Commercial electrical rooms needing reliable distribution for 3-pole circuits
• Light industrial settings where OEM compatibility and sturdy bolt-on mounting are priorities

Upgrade your panel with the Square D QOB340GFI 40 A, 240 V, 3-pole bolt-on breaker from AmpState and enjoy durable protection designed for real-world use.