Siemens CQD390 - 90 A, 480 V, 3-Pole Circuit Breaker | AmpState

The Siemens CQD390 is a 90A, 480V, 3-pole molded-case circuit breaker engineered to shield branch circuits from overcurrent and short-circuit events. Designed to slot into Siemens OEM load centers and panelboards, this unit delivers reliable protection in a compact footprint, making it an ideal choice for residential, commercial, and light industrial applications. Its thermal-magnetic trip unit responds quickly to abnormal conditions, delivering stable, repeatable protection across varying loads and temperatures. Available through AmpState, the CQD390 integrates smoothly with compatible equipment to form a cohesive electrical system.

Key Benefits

• Compact molded-case design maximizes panel space for streamlined electrical layouts.
• Thermal-magnetic trip unit provides stable, repeatable protection against both overloads and short circuits.
• 3-pole configuration ideal for three-phase distribution and equipment feeders.
• OEM compatibility designed to work with matching Siemens load centers and panelboards for straightforward installation and reliable performance.
• Versatile applications suitable for residential panels, commercial electrical distribution, and light industrial setups.

Technical Specifications

• Manufacturer: Siemens
• Part Number: CQD390
• Type: Thermal-magnetic molded-case circuit breaker
• Amperage Rating: 90A
• Voltage Rating: 480V
• Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Ideal Use Scenarios

• Upgrading or expanding commercial distribution panels to safely protect new feeders.
• Installing three-phase equipment in light industrial environments, such as HVAC packs, pumps, and motors.
• Residential and small business panelboards requiring reliable, OEM-compatible protection with a compact form factor.

Compatibility & Installation Considerations

• Designed to match Siemens OEM load centers and panelboards for cohesive performance and straightforward replacement.
• Thermal-magnetic protection minimizes nuisance trips while delivering prompt response to genuine faults.
• When wiring, ensure alignment with specification for 480V three-phase systems and follow standard electrical safety practices.