Siemens Q390 - 90 A, 240 V, 3-Pole Plug-In Circuit Breaker | AmpState

Meet the Siemens Q390 — a dedicated 90 A, 240 V, 3-pole plug-in molded-case circuit breaker designed to safeguard your panelboards and load centers with precision and reliability. Built for fast, dependable protection of branch circuits, it’s the smart choice for residential, commercial, and light industrial applications.

Why this breaker stands out

• Fast plug-in connection delivers quick installation or replacement, minimizing downtime on service calls or panel upgrades.
• Thermal-magnetic trip unit provides stable, repeatable protection by responding appropriately to both overloads and short circuits, reducing nuisance trips and ensuring predictable behavior under fault conditions.
• 3-pole, 90 A, 240 V configuration is ideal for three-phase panelboards and load centers, delivering reliable protection for three hot legs in commercial or light industrial setups.
• OEM-compatible design ensures seamless integration with matching Siemens panelboards and other OEM load centers, supporting a clean, code-compliant installation.
• Versatile protection for a range of applications—from main distribution panels to subpanels and branch circuits—without compromising performance or safety.

Technical specifications at a glance

• Manufacturer: Siemens
• Part number: Q390
• Type: Thermal-magnetic molded-case circuit breaker
• Amperage rating: 90 A
• Voltage rating: 240 V
• Number of poles: 3
• Mounting style: Plug-in
• Application: Branch circuit overcurrent and short-circuit protection

Use cases and ideal scenarios

The Siemens Q390 is purpose-built for environments that demand quick maintenance and dependable safety. Use it to:

• Protect three-phase distribution circuits in commercial or light industrial panelboards, ensuring balanced protection across all legs.
• Upgrade or replace aging breakers in existing Siemens OEM panels with a plug-in solution that reduces installation time.
• Support critical loads in subpanels where rapid replacement and reliable trip performance minimize downtime.
• Provide robust branch-circuit protection for equipment with moderate to high inrush and continuous load profiles, thanks to its thermal-magnetic trip characteristics.

Who benefits most

• Electrical contractors performing panel upgrades or service calls who value speed and reliability.
• Facility managers overseeing commercial spaces or light industrial facilities needing dependable protection with straightforward maintenance.
• Property owners and builders looking for OEM-compatible components that align with Siemens panel ecosystems.

Choosing the Siemens Q390 means prioritizing consistent protection, streamlined installation, and compatibility within Siemens’ panel ecosystems. If you’re upgrading a panel or wiring a new three-phase distribution layout, this 3-pole, 90 A plug-in breaker delivers dependable performance where it matters most.