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Feels well-built and suitable for everyday plant and maintenance use.
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circuit-breaker
Square D QOU390 90A 3P 240V Circuit Breaker, QO | AmpState
| Part Number | QOU390 |
| Series | QO |
| Amperes | 90 |
| Poles | 3 |
| Voltage | 240 |
| Product Type | circuit-breaker |
Regular price
$637.00
Sale price
$637.00
Regular price
Unit price
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Seamless online shopping experience guaranteed with easy shipping and returns policy.
Shop with Confidence: Our Products come with a Reliable Year-Long Warranty.
Square D QOU390 90A 3P 240V Circuit Breaker, QO | AmpState
Regular price
$637.00
Sale price
$637.00
Regular price
Unit price
Product description
Shipping
Introducing the Square D QOU390—a 90 A, 3-pole, 240-volt circuit breaker designed for robust protection in panelboards, load centers, and electrical distribution systems. This unit belongs to the trusted QO family, offering reliable performance in everyday distribution setups and demanding retrofit scenarios.
Why this matters for your project: when you need a part-number-consistent solution for maintenance or retrofit work, the QOU390 provides a precise fit without changing your existing footprint. Keeping the same part number simplifies ordering, inventory management, and coordination with nearby protective devices, so you can keep projects on track and on schedule.
Key specifications
- Manufacturer: Square D
- Part number: QOU390
- Product type: Circuit Breaker
- Amperage: 90 A
- Pole configuration: 3 Poles
- Voltage rating: 240 V
- Availability: AmpState
What makes it uniquely valuable
The QOU390 is purpose-built for reliable protection in electrical distribution systems. Its 3P design supports multi-phase circuits common in commercial and industrial panelboards, while the 90 A rating provides solid protection for branch circuits without unnecessary nuisance tripping. Staying within the Square D QO family means compatible mounting geometry and electrical characteristics, reducing surprises during installation and ensuring coordinated protection with existing devices.
Ideal use cases
- Retrofitting older panelboards where a 3-pole, 90 A, 240 V breaker is required
- Maintenance planning that benefits from a consistent, inventory-friendly part number
- New installations that align with QO-series panelboard configurations and wiring schemes
Guidance for compatibility
Need help confirming fit with a specific panel or distribution system? AmpState is ready to assist—simply reference the QOU390 and your equipment requirements to verify compatibility and ensure safe, compliant operation.
Upgrade or maintain your electrical distribution with confidence—choose the Square D QOU390 90A 3P 240V circuit breaker, available from AmpState.
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What Our Customers Say
General feedback we often hear from customers purchasing industrial electrical parts.
Verified
Lead time was reasonable and the part matched expectations when it arrived.
Procurement · Ontario
Verified
Good value for industrial use. Customers mention easy installation.
Service tech · Field work
