Square D H366 Heavy Duty Safety Switch – 600A – 3 Pole – 600V AC/DC – Fusible Disconnect – NEMA 1 Indoor Enclosure

The Square D H366 Heavy Duty Safety Switch is a high-capacity fusible disconnect switch designed for demanding commercial, industrial, and power distribution applications where reliable equipment isolation and overcurrent protection are critical. Manufactured by Schneider Electric under the Square D brand, this heavy-duty safety switch is rated for 600A and supports systems operating up to 600V AC/DC.

Featuring a 3-pole, 3-wire configuration, the H366 provides a safe and dependable means of disconnecting power to large motors, feeders, service entrance equipment, and industrial machinery. When equipped with Class H fuses, the switch delivers effective short-circuit and overcurrent protection while ensuring safe isolation for maintenance and servicing operations.

The switch incorporates a quick-make, quick-break operating mechanism that provides fast and positive contact operation, enhancing both safety and reliability. Built to withstand rigorous industrial use, the H366 exceeds standard heavy-duty performance requirements and offers long mechanical service life in demanding environments.

Housed in a NEMA 1 indoor enclosure, the switch is ideal for installation in electrical rooms, manufacturing facilities, commercial buildings, and other protected indoor locations. Its robust construction and high horsepower rating make it suitable for large motor and power distribution applications requiring dependable switching performance.

Specifications

• Brand: Square D by Schneider Electric
• Manufacturer: Square D Co. / Schneider Electric
• Part Number: H366
• Model: E4
• Category: Fusible Heavy Duty Safety Switch
• Device Type: Heavy Duty Safety Switch
• Disconnect Type: Fusible
• Switch Action: Single Throw
• Number of Poles: 3 Pole
• Circuit Configuration: 3-Phase, 3-Wire
• Current Rating: 600A
• Voltage Rating: 600V AC/DC
• Fuse Class: Class H
• Horsepower Rating: Up to 500 HP
• Enclosure Type: NEMA 1 Indoor

Electrical Performance

• Rated Current: 600A
• Maximum Voltage: 600V AC/DC
• Phase Configuration: 3-Phase
• Fuse Protection: Class H Fusible Design
• Quick-Make / Quick-Break Mechanism: Yes
• Suitable for Heavy-Duty Industrial Applications: Yes
• Motor Rating: Up to 500 HP

Mechanical & Construction Features

• Heavy-duty industrial-grade construction
• Single-throw switching mechanism
• Fusible disconnect design
• Quick-make, quick-break operation
• Visible blade disconnect mechanism
• Large-capacity power switching capability
• Designed for frequent operation and long service life
• Enclosed rotary disconnect configuration

Dimensions & Weight

• Width: 27.88 in.
• Depth: 10.13 in.
• Height: 50.00 in.

Applications

• Industrial power distribution systems
• Service entrance disconnect applications
• Large motor control and isolation
• Manufacturing facilities
• Commercial electrical infrastructure
• Distribution feeders and switchgear systems
• Heavy industrial equipment disconnecting means
• Electrical rooms and power control centers

Standards & Certifications

• UL Listed
• Complies with applicable UL safety switch requirements
• Designed for heavy-duty commercial and industrial applications
• Suitable for service and feeder disconnect applications when installed per applicable codes

Environmental Ratings

• Enclosure Rating: NEMA 1
• Installation Location: Indoor Use Only
• Designed for protected electrical environments
• Durable construction for industrial service conditions
• Long-term reliability in commercial and industrial installations

Additional Information

• UPC: 785901451891
• UNSPSC: 39122205
• Category: Enclosed Rotary Safety / Disconnect Switch
• Prop 65 Warning: Contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.