Square D QO340EPD - 40 A, 240 V, 3-Pole Plug-In Circuit Breaker | AmpState

The Square D QO340EPD is a 40A, 240V, 3-pole plug-in molded case circuit breaker designed for dependable branch circuit protection in panelboards and loadcenters. With a fast plug-in connection, it supports quick installation and effortless replacement when service needs change, minimizing downtime and maintenance time.

Key specifications

• Manufacturer: Square D
• Part Number: QO340EPD
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 40A
• Voltage Rating: 240V
• Number of Poles: 3
Mounting Style: Plug-in
• Application: Branch circuit overcurrent and short-circuit protection

Why this model stands out

• Rapid plug-in installation: A streamlined connection that reduces on-site wiring time and simplifies panel maintenance.
• Thermal-magnetic trip unit: Delivers stable, repeatable protection by responding to both prolonged overloads and sudden short circuits, helping prevent nuisance trips or equipment damage.
• OEM-compatible design: Engineered for seamless compatibility with matching Square D panelboards and load centers, ensuring reliable fit and performance.
• Versatile performance range: Suitable for residential, commercial, and light industrial applications where dependable protective switching is essential.

Ideal applications and use cases

Use the QO340EPD to safeguard branch circuits in panels that serve lighting, outlets, and equipment runs. Its 3-pole configuration is well-suited for 3-phase systems or multi-pole protection within mixed-use installations. Ideal scenarios include panelboard upgrades, breaker replacements in aging systems, or new builds that require precise 40A protection at 240V.

Compatibility and installation considerations

Designed to pair with Square D OEM load centers and panelboards, this plug-in breaker preserves system integrity and simplifies field replacements. When installing, ensure the panelboard is listed for QO series devices and follow standard electrical safety practices. The 3-pole configuration supports balanced protection across phases, helping maintain system stability in commercial and light industrial environments.

Performance you can rely on

With a thermal-magnetic trip mechanism, the QO340EPD provides predictable, instantaneous response to short circuits and reliable thermal protection during sustained overcurrent events. This combination helps minimize downtime, protects connected equipment, and maintains electrical safety in busy panels where reliability matters most.