Square D Q1B340 Circuit Breaker, 40A, 3-Pole, 240V

The Square D Q1B340 circuit breaker is a rugged, industrial-grade protection device designed for 3‑phase, 240V systems. With a 40 A rating across three poles, it delivers dependable overcurrent protection for critical equipment in service, maintenance, and replacement projects. As a member of the Q1B series, this breaker is built to drop into compatible Square D panels and MCCs with straightforward installation and reliable performance. Key specifications at a glance

• Amperage: 40 A
• Poles: 3
• Voltage: 240 V
• Series / Part Number: Q1B series, Q1B340
• Manufacturer: Square D

Why this breaker is a smart choice for industrial protection

Designed for industrial electrical service, maintenance, and replacement work, the Q1B340 provides precise overcurrent protection for three‑phase circuits. Its 40A rating is well-suited for mid‑sized feeders and motor control scenarios where reliable interruption during overloads or short circuits is essential to protect downstream equipment and minimize downtime.

Use cases and real‑world applications

• Replacing a failed 3‑pole breaker in an industrial control panel or MCC rack
• Upgrading legacy protection to a modern, compatible Q1B series unit
• Protecting 3‑phase 240V feeders feeding motors, drives, or control circuits
• Retrofits in manufacturing lines, packaging systems, or processing equipment

How to verify compatibility and ensure a proper fit

Always confirm fit by part number and application requirements. The Q1B340 is part of the Square D Q1B family, so match it to your panel or controller’s specifications and the 240V, three‑phase load it will protect. If you’re unsure about compatibility, our team can help verify part numbers and suitability for your exact setup.

Practical tips for installation and performance

• Double‑check that your system is operating at 240V three‑phase and that 40 A protection aligns with the load calculations for your circuit
• Ensure the enclosure and bus rating are compatible with the Q1B340 and its mounting requirements
• Plan for proper wiring practices and secure terminations to maintain reliable operation and easy future maintenance

In short, the Square D Q1B340 is a precise, compatible choice for safeguarding 3‑phase 240V circuits in demanding industrial environments. By matching the part number Q1B340 to your application, you gain dependable protection, streamlined replacement, and peace of mind that your equipment stays safeguarded under normal and fault conditions.