Square D QOU370 - 70 A, 240 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D QOU370—a 70A, 240V, 3-pole bolt-on molded case circuit breaker designed to shield your electrical system from overcurrent and short circuits. Built for panelboards and loadcenters, this MCCB is the reliable choice when you need durable, consistent protection in residential, commercial, or light industrial settings.

• Secure bolt-on mounting — a rigid, vibration-resistant bus connection that stays tight through equipment start-ups, servicing, and building movement.
• Thermal-magnetic trip unit — delivers stable, repeatable protection curves for both gradual overcurrent and rapid short-circuit events, reducing nuisance trips and downtime.
• OEM-ready compatibility — engineered to pair with matching Square D loadcenters and panelboards, ensuring correct fit, electrical characteristics, and protection performance.
• Versatility for multiple environments — from home electrical rooms to small commercial spaces and light industrial panels, it handles a range of feeders and branch circuits.

Technical snapshot

• Manufacturer: Square D
• Part Number: QOU370
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 70 A
• Voltage Rating: 240 V
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Why this matters in real-world installs

The 3-pole configuration is ideal for 3-phase systems common in commercial spaces and light industrial environments, while the 240 V rating covers typical feeders for panels and subpanels. The bolt-on design simplifies field mounting and servicing, delivering robust mechanical stability in equipment rooms, mechanical spaces, or retrofit projects where vibration or movement is a concern.

Practical scenarios

• Upgrading a residential main or sub-panel where a reliable 70 A feeder breaker is needed for a balanced three-phase or single-phase feeder in a 3-pole arrangement.
• Installing a new panel in a small office suite, retail shop, or service room where space is tight and a secure, vibration-free connection matters.
• Replacing a failed MCCB in light industrial equipment feeders that experience regular start/stop cycles and minor vibrations from HVAC or rack motion.

What you get with Square D QOU370

• Proven protection from overcurrent and short circuits backed by Square D engineering and warranty support.
• Confidence knowing the breaker is designed to work with the OEM panels in your electrical distribution system, minimizing compatibility concerns.
• Long-term reliability through a rugged bolt-on mounting and a dependable thermal-magnetic trip unit.

Tips for optimal performance

• Verify panel compatibility with matching OEM load centers and panelboards before installation.
• Follow the panel manufacturer's torque specifications and installation instructions to ensure a secure mounting and proper trip performance.
• Keep spare QOU370 units on hand in maintenance rooms or stocking programs to minimize downtime during panel upgrades or repairs.

In short, the Square D QOU370 is a purpose-built solution for robust, reliable circuit protection in 3-phase and single-phase configurations where 70 A at 240 V is the right fit. Whether you’re upgrading an existing panel, constructing a new electrical room, or stocking essential spare parts, this bolt-on MCCB delivers the consistent protection and durable performance you expect from Square D.