Square D QMB325WT3 – 400A, 240V, 3-Pole Fusible Panelboard Switch – QMB Series (Class T fuse version)

Meet the Square D QMB325WT3 — a dedicated fusible panelboard switch from Schneider Electric’s trusted QMB Series. Engineered for 400 A at 240 V in a 3-pole configuration, this unit delivers reliable load disconnect and robust overcurrent protection when paired with the appropriate Class T fuse. It’s the focused solution for clean, safe distribution in QMB fusible panelboards.

Why this fusible panelboard switch stands out

• Integrated fuse-based protection that provides instantaneous overcurrent protection to protect feeders and equipment, reducing the risk of damage during faults.
• Class T fuse compatibility tailored for coordinated protection within QMB fusible panelboards, enabling selective protection so only the affected section drops offline during a fault.
• High reliability in demanding environments with a 200 kAIC interrupt rating, ensuring safe isolation during maintenance or emergencies.
• Three-pole design ensures balanced switching across hot legs, preserving system stability and simplifying sequencing during fault conditions.

Ideal use cases

• New installations or retrofit upgrades in commercial and light industrial electrical distributions that require a dependable 400 A disconnect with fuse protection.
• Panelboard upgrades where a compact, three-pole solution protects feeders feeding motors, transformers, or distribution circuits.
• Service entrances or main distribution panels that demand clear isolation points with coordinated protection.

How it improves your operation

By combining a robust disconnect with proven fuse-based protection, the QMB325WT3 simplifies maintenance planning and minimizes downtime. The three-pole configuration ensures even performance across all phases, maintaining circuit balance during faults. When used with the specified Class T fuses, it delivers predictable, coordinated protection that aligns with safety standards and electrical codes.

Practical considerations and best practices

• Ensure compatibility with QMB fusible panelboards and use only the rated Class T fuses specified for this configuration.
• Verify installation in accordance with local electrical codes and Schneider Electric installation guidelines.
• Plan regular maintenance checks for fuse continuity and panelboard integrity to maintain dependable protection.

Who should consider the QMB325WT3

• Electricians and facility engineers responsible for reliable, code-compliant power distribution in commercial or light industrial settings.
• Projects seeking coordinated, selective protection for feeders feeding motors, transformers, or critical distribution circuits.
• Engineers evaluating service entrance or main distribution upgrades where a compact, highly protected disconnect is required.