Square D QMB365W - 400A, 600V, 3-Pole, Fused Disconnect Switch

Engineered for demanding industrial and commercial environments, the Square D QMB365W 400A, 600V fused disconnect switch delivers dependable electrical isolation with built-in safety features that support lockout/tagout procedures and safe maintenance.

Designed to interrupt fault currents cleanly while under load, this three-pole disconnect switch ensures quick, reliable disconnection when you need it most. Its robust construction is built to withstand the rigors of continuous operation in electrical rooms, equipment closets, and service panels.

Key benefits

• High-current capability: 400A at a 600V rating handles large three-phase circuits with confidence.
• Fused protection: integrated fusing provides a controlled interruption path, improving safety and reducing arcing risk during isolation.
• Three-pole design: removes all three phases in one simple action for comprehensive system shutdown.
• Lockout/Tagout readiness: compatibility with standard LOTO practices to keep personnel safe during maintenance and service work.
• Durable, field-ready construction: designed for longevity in busy industrial environments where reliability matters most.

Ideal use cases

The QMB365W is well-suited as the primary disconnect for large equipment, motors, conveyors, and HVAC or processing lines where a dedicated, fused isolation point is required. Use it in service panels or motor control centers to enable safe maintenance, provide reliable isolation under load, and support rapid re-energization after work is completed.

Technical specifications at a glance

• Amperage Rating: 400A
• Voltage Rating: 600V
• Number of Poles: 3-Pole
• Product Type: Fused Disconnect Switch
• Brand: Square D
• Model: QMB365W

Note: Ensure compliance with local electrical codes and follow proper lockout/tagout procedures when using this disconnect switch. For installation, consult a qualified electrician and reference the product documentation for fuse compatibility and mounting guidelines.