Square D QOB120AFI - 20 A, 1-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D QOB120AFI — a reliable 20A, 1-pole bolt-on molded case circuit breaker engineered for dependable branch-circuit protection in panelboards and loadcenters. Its rugged bolt-on mounting creates a solid bus connection, minimizing vibration-induced movement and ensuring consistent performance in busy electrical environments.

Why this breaker stands out

• Secure bolt-on mounting provides a rigid, vibration-resistant connection to the bus, reducing loosening risks in panels and during equipment operation.
• Thermal-magnetic trip unit delivers stable, repeatable protection across a wide range of temperatures and load conditions, helping prevent nuisance trips while safeguarding circuits.
• 1-pole, 20A rating is ideal for protecting individual branch circuits such as lighting, outlets, or small equipment branches without over-tripping other circuits.
• OEM-compatible design is built to fit with matching Square D load centers and panelboards, simplifying replacements and upgrades.
• Versatile applications suitable for residential, commercial, and light industrial environments where reliable, compact protection is needed.

Ideal use cases

• Replacing a failed or aging breaker in Square D panelboards and loadcenters without changing the entire enclosure.
• Upgrading branch circuits in residential wiring, small offices, retail spaces, or light industrial setups that need dependable overcurrent protection.
• Retrofitting or expanding panel capacity while maintaining consistent protection characteristics across circuits.
• Situations requiring a compact, bolt-on solution that resists vibration and optimizes bus connections.

Technical overview

• Manufacturer: Square D
• Part Number: QOB120AFI
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 20A
• Number of Poles: 1
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Practical considerations and tips

• Ensure you’re installing the QOB120AFI into a compatible OEM panelboard or load center designed for bolt-on molded case breakers.
• Follow standard electrical safety procedures and the panel’s installation instructions when performing replacements or upgrades.
• Because the unit is thermal-magnetic, it responds quickly to overcurrent events while minimizing unnecessary tripping from temporary surges.