Square D 31055-366-50 - 200A, 600V, 3-Pole, Fusible, Disconnect Switch

The Square D 31055-366-50 is a rugged 200A, 600V, 3-Pole fusible disconnect switch engineered to deliver dependable on/off isolation with integrated overcurrent protection in demanding industrial and commercial environments.

Specifically designed for motor disconnects, panelboards, and branch circuits, this compact switch combines a sturdy enclosure with a clearly accessible disconnect lever and field-replaceable fuses. It offers straightforward maintenance and minimizes downtime, keeping critical equipment running when it matters most.

Key specifications

• Model: 31055-366-50
• Amperage: 200A
• Voltage: 600V
• Poles: 3-Pole
• Fusible: Fusible

Why this fusible disconnect stands out

• Reliable power isolation with a dedicated on/off mechanism that clearly breaks the circuit when service is needed.
• Integrated overcurrent protection via replaceable fuses, reducing the need for separate protective devices in many panel and motor applications.
• Compact, maintainable design suited for tight spaces in industrial and commercial installations, while still delivering robust protection.
• Balanced three-pole configuration ensures coordinated disconnects across all phases, helping prevent partial energization and improving fault handling.

Ideal use cases

• Motor control circuits where rapid, dependable shutdown is essential for safety and mechanical protection.
• Panelboard feeder sections requiring localized disconnect and overcurrent protection in a single, manageable unit.
• Branch circuits in environments with demanding duty cycles, where a compact fusible switch minimizes space without compromising reliability.

Practical benefits and how it helps you

With the 31055-366-50, you gain a clear, actionable isolation point for maintenance and fault isolation, improved protection for downstream equipment, and a straightforward path to fuse replacement when protection devices trip. Its rugged construction is well-suited to industrial floors, maintenance bays, and commercial facilities that demand durable electrical protection without sacrificing ease of service.

Tips for installation and upkeep

• Ensure the installed fuses match the motor or circuit’s start-up and running current requirements to maintain proper protection without nuisance trips.
• Coordinate with upstream protective devices to optimize short-circuit protection and select appropriate fuse types and ratings.
• During maintenance, inspect the enclosure for corrosion or contamination and verify that the disconnect lever moves freely and fully.
• Follow all applicable electrical codes and the manufacturer’s recommendations for mounting, wiring, and fuse replacement procedures.

Choose the Square D 31055-366-50 when you need a dependable, space-efficient fusible disconnect that delivers solid isolation and integrated protection for demanding motor and distribution applications at up to 200A and 600V.