Square D QOB3401021 - 40 A, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D QOB3401021 — a 40A, 3-pole bolt-on molded case circuit breaker designed to guard branch circuits against overcurrent and short circuits in panelboards and loadcenters. This unit combines rugged construction with precise thermal-magnetic trip performance, delivering dependable protection when it matters most.

Key advantages include a secure bolt-on mounting that creates a rigid, vibration-resistant bus connection, a thermal-magnetic trip unit for stable, repeatable protection across varying loads, and seamless compatibility with matching OEM load centers and panelboards. This breaker is well-suited for residential, commercial, and light industrial applications, making it a versatile choice for electricians and facilities managers alike.

Why this breaker stands out

• Secure bolt-on mounting: A rigid connection minimizes movement and loosening in vibration-prone panels, helping maintain consistent protection over time.
• Thermal-magnetic trip unit: Delivers repeatable protection for both overloads and short circuits, even as circuits heat up under heavy use.
• 3-pole, 40A design: Suited for small three-phase distribution, motor loads, and branched circuits that require reliable tri-pole protection.
• OEM compatibility: Engineered to drop into matching Square D OEM load centers and panelboards for a hassle-free upgrade or replacement.
• Versatile application: Suitable for residential, commercial, and light industrial environments where dependable branch-circuit protection is essential.

Ideal use cases

• Three-phase motor circuits in light industrial equipment or commercial HVAC controls.
• Residential or commercial subpanels needing reliable 40A protection on specific branches.
• Panelboard upgrades or replacements where consistent thermal-magnetic protection and secure mounting are critical.

Technical snapshot

• Manufacturer: Square D
• Part number: QOB3401021
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 40A
• Poles: 3
• Mounting style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Designed for straightforward installation and long-term reliability, the Square D QOB3401021 provides robust protection aligned with OEM specifications. Available from AmpState, it offers authentic Square D components that you can trust to perform consistently in your electrical distribution system.