Square D QMB-323-MW - 100A, Disconnect Switch

The Square D QMB-323-MW is a rugged, industrial-grade Disconnect Switch engineered to provide safe, reliable electrical isolation where it matters most. With a 100A rating, it delivers dependable disconnection under load, making maintenance, troubleshooting, and servicing safer and faster in busy commercial and industrial environments. Designed to support proper lockout/tagout procedures, this switch helps you uphold safety standards without sacrificing performance or reliability.

Key benefits that set the QMB-323-MW apart

• Reliable under load — engineered to open circuits cleanly even when circuits are energized, reducing the risk of arcing or incomplete disconnection during critical maintenance.
• Lockout/Tagout friendly — built to integrate seamlessly with standard lockout/tagout practices, helping your team meet safety compliance with confidence.
• Industrial-grade durability — designed for demanding environments found in factories, warehouses, and large facilities, delivering long-term performance with minimal downtime.
• Straightforward installation — compatible with common panel and enclosure configurations, enabling quicker installation and easier serviceability.
• Clear identification and control — provides a decisive, easy-to-operate disconnect action that clearly communicates its status to maintenance staff and operators.

Ideal applications

• Motor feeders and power distribution circuits in manufacturing floors
• Service entrances and main disconnect points in commercial facilities
• Panelboards and switchgear assemblies requiring safe isolation during maintenance
• Emergency isolation points where rapid, dependable disconnection is essential

How it works

In normal operation, the QMB-323-MW sits as a standard disconnect in the supply path. When maintenance or servicing is required, the switch is operated to the off position to interrupt the circuit. This action provides a reliable, observable open-circuit condition, enabling lockout/tagout procedures to be applied safely. When re-energizing, rotate the handle to the on position to restore power with a controlled, verified disconnect-release process.

Specifications at a glance

• Amperage rating: 100A
• Product type: Disconnect Switch
• Brand: Square D
• Model: QMB-323-MW

Practical tips for optimal use

• Pair the QMB-323-MW with your facility’s lockout/tagout devices to maintain compliant safety procedures during service work.
• Verify enclosure fit and mounting compatibility within your existing panel or switchgear before installation to ensure a seamless retrofit.
• Schedule periodic functional checks to confirm clean open/close operation and to prevent sluggish actuation in high-demand environments.
• Maintain clear labeling around the disconnect point to communicate its purpose and ensure quick identification during emergencies.

Why choose Square D for electrical safety and reliability?

Square D brings decades of electrical engineering expertise to industrial and commercial power systems. The QMB-323-MW embodies this legacy with a purpose-built design that emphasizes safe isolation, durable construction, and straightforward maintenance. If your priority is a dependable disconnect switch that supports lockout/tagout procedures and provides robust performance under load, the QMB-323-MW is a practical, future-ready choice for your electrical safety and reliability needs.