Zinsco | QB40 | Circuit Breaker | 1-Pole | 120V | Bolt-On

Introducing the Zinsco QB40 1-Pole 120V Bolt-On circuit breaker — a purpose-built solution for maintenance, retrofit, and replacement tasks where exact specs matter. Identified by the QB40 part number, this breaker is designed to match the form and function of compatible Zinsco panels, restoring reliable overcurrent protection quickly and confidently.

• Single-pole, 120-volt operation: Protects a dedicated branch circuit with straightforward, reliable trip behavior.
• Bolt-On mounting: Secure, tool-friendly installation that maintains solid electrical contact in the panel.
• Part-number-driven compatibility: Use QB40 as the best reference to ensure a correct fit with your panel and hardware.
• Ideal for maintenance, retrofit, and replacement: Perfect when upgrading or restoring older electrical systems that require this exact specification.
• Authentic Zinsco design alignment: Engineered to meet the brand’s safety and performance expectations for 1-pole 120V circuits.

Who this is for: electricians, facility maintenance teams, and electrical contractors working on Zinsco panel systems that require a precise QB40 replacement. Use cases range from service calls to panel retrofits where downtime matters and you need a reliable, compatible breaker on hand.

How to ensure you get the right part: Before ordering, directly compare your panel’s labeling to confirm compatibility. The QB40 part number is your strongest reference, but always verify voltage (120V) and pole configuration (1-Pole) match your circuit requirements. This breaker is intended for 1-pole 120V circuits in compatible Zinsco panel assemblies and should be installed by qualified personnel.

Key specs at a glance:

• Pole configuration: 1-Pole
• Voltage rating: 120V
• Mounting: Bolt-On
• Brand/series: Zinsco QB40
• Reference: QB40 part number for compatibility