Square D QMB-364 - 200A, 600V, 3-Pole, Fusible, Switch

Square D QMB-364 is a rugged, reliable fusible switch engineered for on/off isolation and robust overcurrent protection in demanding industrial and commercial environments. With a 200A rating and a 600V maximum, this 3-pole device is purpose-built for medium-duty motor disconnects, panelboards, and branch circuits where dependable protection and simple maintenance matter most.

Why this fusible switch stands out

• Integrated protection and control — combines switching capability with fusible protection, giving you quick isolation and clear fault interruption in a single, compact package.
• Three-phase reliability — 3-pole design ensures all three phases disconnect together, preventing half-bridging scenarios that can harm equipment and compromise safety.
• High-current, high-voltage readiness — rated for 200A at up to 600V, making it suitable for a wide range of motors, transformers, and distribution circuits.
• Maintenance-friendly by design — a compact form factor with accessible fuse components simplifies routine checks and fuse replacement, reducing downtime during service windows.
• Industrial-grade robustness — built to endure the realities of busy facilities, from rugged environments to demanding operating cycles, while delivering reliable isolation when needed.

Key specifications at a glance

• Model: QMB-364
• Amperage: 200A
• Voltage: 600V
• Poles: 3-Pole
• Fusible: Fusible switch for integrated protection

Ideal use cases

Perfect for motor disconnects where you need both a switch and fuse in one unit, panelboards requiring localized protection, and branch circuit protection in commercial or light-industrial applications. If you’re upgrading from a plain disconnect, the QMB-364 delivers enhanced safety and faster fault response without expanding your control cabinet footprint.

How it protects your system

The fusible element provides overcurrent protection, cutting power quickly when a fault is detected. The 3-pole design guarantees synchronized disconnection of all phases, helping prevent voltage imbalances and protecting downstream equipment from damage. This setup simplifies code compliance for protective routing while keeping maintenance straightforward.

Practical tips for best results

• Pair this switch with appropriately rated fuses to maintain the intended protection level and ensure violation-free code compliance.
• Use in appropriate panel enclosures where clear visibility and safe access for maintenance are available.
• Schedule regular fuse inspections and replace any damaged or degraded fuses promptly to maintain reliable protection margins.
• When selecting a disconnect for a motor load, consider the QMB-364 for its compact footprint without sacrificing protection or serviceability.

Who this is for

Facilities managers, electrical contractors, and plant engineers seeking a durable, easy-to-maintain fusible switch for motor control centers, switchgear enclosures, and protected branch circuits will appreciate the Square D QMB-364’s balance of performance and practicality.