Siemens CQD120 - 20 A, 277 V, 1-Pole Circuit Breaker | AmpState

Introducing the Siemens CQD120 — a compact, reliable 20A, 277V, 1-pole molded case circuit breaker designed to protect branch circuits in panelboards and load centers. Built to integrate with Siemens OEM panels, it delivers a precise, drop-in solution for modern electrical distributions.

Designed for real-world protection, the CQD120 uses a thermal-magnetic trip unit to deliver stable, repeatable protection across temperature swings and varying load conditions. The thermal element guards against overloads, while the magnetic element provides fast response to short circuits, helping minimize damage and downtime in your electrical system.

• Space-efficient design: Compact molded case saves panel space, enabling higher circuit density without compromising protection.
• Durable, reliable protection: Thermal-magnetic trip delivers predictable operation for residential, commercial, and light industrial environments.
• Seamless compatibility: Designed to fit Siemens OEM load centers and panelboards, simplifying replacements and upgrades.
• 277V versatility: Ideal for commercial lighting and other 277V circuits, expanding your panel’s capability beyond standard 120/240V applications.

Key specifications at a glance

• Amperage: 20A
• Voltage: 277V
• Number of Poles: 1
• Type: Thermal-magnetic molded case circuit breaker
• Application: Branch circuit overcurrent and short-circuit protection

Ideal applications and use cases

The CQD120 is well-suited for wiring closets, commercial lighting panels, and light-industrial distribution where dependable 1-pole protection is essential. Use it to guard circuits feeding luminaires, receptacles, or control circuits operating at 277V, delivering consistent protection for daily, mission-critical loads.

Installation and performance tips

Install in Siemens panelboards or compatible OEM panels, aligning with bus bars and lugs for secure termination. Adhere to the installation torque and wiring guidelines provided by Siemens to ensure optimal trip performance and reliability over the life of the panel.

Choosing the CQD120 means selecting a breaker designed for coordinated protection within Siemens ecosystems. Its compact form factor, precise thermal-magnetic protection, and 277V readiness help you maximize panel space, streamline maintenance, and keep critical commercial and light-industrial circuits safeguarded.