Square D QOB220-1021 QOB2201021 - 20A 2 Pole Miniature Circuit Breaker

This breaker is designed exclusively for Square D NQ and NQOD panelboards. It bolts directly to the panelboard bus bar, providing a secure, vibration-resistant connection required in commercial and industrial applications.

The 1021 suffix indicates the breaker includes a factory-installed 120/240VAC shunt trip. This accessory allows the breaker to be tripped remotely using a push-button or control relay, which is commonly used for emergency shutdown systems.

Bolt-on breakers like the QOB series secure directly to the panelboard bus bar using screws. This creates a highly stable mechanical and electrical connection that resists loosening from vibration, unlike standard plug-on QO breakers that rely on spring tension.

The pressure plate terminals are rated for both aluminum and copper conductors ranging from 14 AWG to 8 AWG. Always ensure proper torque is applied during installation to maintain a secure connection and prevent terminal overheating.

Yes, in addition to its standard 120/240VAC rating, this breaker is rated for 48VDC systems with a 5kA interrupting capacity. This allows it to be used in low-voltage DC control panels and battery circuits.

No. Standard QO load centers only accept plug-on breakers. The QOB220-1021 features a bolt-on mounting design that is only compatible with commercial NQ and NQOD panelboards.

The thermal element provides long-time protection by tripping in response to sustained overloads, preventing wire insulation damage. The magnetic element provides instantaneous tripping when it detects high-fault short circuits.

Yes, it features the Square D Visi-Trip indicator. When the breaker trips due to a fault or remote shunt trip activation, a red flag appears in the indicator window, allowing electricians to quickly locate the tripped breaker in a crowded panel.

The QO220-1021 is a plug-on circuit breaker for residential load centers, whereas the QOB220-1021 is a bolt-on circuit breaker for commercial panelboards. Both models share the same 20A rating, 2-pole configuration, and factory-installed shunt trip.

No, this miniature circuit breaker features fixed thermal and magnetic trip settings. It is calibrated at the factory to provide consistent protection for 20A circuits and cannot be modified in the field.