Square D Q1B390 Circuit Breaker, 90A, 3-Pole, 240V

Introducing the Square D Q1B390 circuit breaker — a rugged, reliable solution built for industrial electrical service, maintenance, and replacement projects. With a 90 Amp rating, three poles, and 240V operation, this breaker is purpose-built to safeguard demanding three‑phase circuits in commercial and industrial environments. Verify compatibility using the part number Q1B390 and your panel’s application requirements.

Key specifications

• Manufacturer: Square D
• Part number: Q1B390
• Product type: Circuit Breaker
• Amperage: 90 A
• Poles: 3
• Voltage: 240V

Why this breaker stands out

The Q1B390 is designed for industrial service scenarios where dependable protection and robust performance are non-negotiable. Its 3-pole design is ideal for 3-phase systems, providing coordinated interruption across all phases to help prevent equipment damage and downtime. Manufactured by Square D, it integrates with existing Square D panels and distribution setups, offering a cohesive, reliable protection solution for mid-to-large load circuits.

Ideal use cases

• Industrial service upgrades and panel replacements in manufacturing facilities
• Maintenance projects requiring a dependable 90 A, 3-pole, 240V circuit breaker
• Replacement of worn or outdated breakers in heavy-duty electrical distributions

Compatibility and purchasing guidance

Notes: Verify fit by part number and application requirements. If you’re unsure about compatibility, you’re not alone — we’re here to help. Message us to confirm that Q1B390 matches your panel model, wiring configuration, and load needs before purchasing.

Practical installation and care tips

• Turn off power and lockout/tagout prior to installation or service.
• Ensure the breaker is installed in an appropriate Square D panel compatible with the Q1B390.
• Follow all manufacturer installation instructions and local electrical codes for safe, compliant operation.