Square D QOB3701021 - 70 A, 3-Pole Bolt-On Circuit Breaker | AmpState

Introducing the Square D QOB3701021, a 70 Amp, 3-pole bolt-on molded case circuit breaker engineered for dependable branch circuit protection in panelboards and load centers.

Built for durability and steady performance, this unit features a secure bolt-on mounting that delivers a rigid, vibration-resistant bus connection—minimizing loosening risk in demanding electrical environments.

The thermal-magnetic trip unit provides stable, repeatable protection. It responds to both sustained overloads (thermal) and short circuits (magnetic), helping prevent wiring and equipment damage while minimizing nuisance trips during normal load fluctuations.

Key capabilities at a glance:

• 70 A, 3-pole design: supports 3-phase circuits with common-trip protection where required
• Bolt-on mounting: secure installation in compatible panelboards and loadcenters
• Molded case construction: robust for residential, commercial, and light industrial applications
• Compatibility: designed to work with matching OEM loadcenters and panelboards
• Protection focus: branch circuit overcurrent and short-circuit protection

Technical snapshot

• Manufacturer: Square D
• Part Number: QOB3701021
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 70 A
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Who is this for? Electricians, facilities managers, and homeowners maintaining panelboards and load centers will appreciate the reliability and compatibility of the QOB3701021. It’s ideal for new installations in commercial spaces or retrofits in residential settings where a three-pole protection device is required for balanced or three-phase load scenarios.

Why choose this unit over generic breakers? The combination of secure bolt-on reliability, proven thermal-magnetic trip performance, and compatibility with Square D OEM panel systems ensures a component designed for long-term reliability in real-world electrical installations. Selecting a factory-matched breaker reduces the risk of nuisance trips and fitment issues often associated with aftermarket substitutes.

Practical tips for installation and use:

• Verify your panelboard model is compatible with bolt-on QOB series breakers before installation
• Align the 3-pole unit with the bus bars and tighten bolts to the recommended torque to ensure a solid connection
• Schedule periodic inspections of connections to maintain low-resistance paths and reduce heating under load
• Ensure the 70 A rating matches your branch circuit design to minimize unnecessary trips

With the Square D QOB3701021, you gain a purpose-built solution for reliable branch circuit protection—combining rugged construction, precise trip performance, and seamless compatibility with Square D panel systems.