The **QO2125VH1200** is a specific high-performance miniature circuit breaker manufactured by Square D (Schneider Electric). It belongs to the **QO (Quick-Open)** family, which is widely regarded for its "visu-trip" indicator and reliability in industrial and commercial applications. --- ### 1. Technical Specifications The following table outlines the primary electronic and physical characteristics of this component: | Feature | Specification | | :--- | :--- | | **Product Type** | Miniature Circuit Breaker | | **Number of Poles** | 2-Pole | | **Current Rating (Amperage)** | 125 Amperes | | **Voltage Rating** | 120/240 V AC | | **Interrupt Rating (AIR)** | 22,000 Amperes (22kA) | | **Mounting Type** | Plug-On | | **Wire Size Range** | #4 to 2/0 AWG (Copper/Aluminum) | | **Trip Unit Type** | Thermal-Magnetic | --- ### 2. Breakdown of the Model Number Understanding the nomenclature helps identify the "electronic DNA" of the part: * **QO**: Standard Square D Plug-on format. * **2**: Indicates a 2-pole construction (occupies two spaces in the load center). * **125**: The continuous current rating is 125 Amps. * **VH**: Indicates "High Interrupting" capacity. While standard QO breakers are often 10kA, the VH suffix denotes a **22kA** rating, making it suitable for locations near a power transformer where fault currents are high. * **1200**: This suffix typically denotes specific packaging or a bulk factory sub-designation, though the core specs remain standard to the QO2125VH line. --- ### 3. Key Electronic Functions #### A. Thermal-Magnetic Tripping This breaker utilizes two methods of protection: 1. **Thermal Protection:** Uses a bimetallic strip that bends in response to heat. This handles **overloads** (slow, sustained current above 125A). 2. **Magnetic Protection:** Uses an electromagnetic coil to provide instantaneous tripping during **short circuits** (sudden, massive spikes in current). #### B. The Visi-Trip Indicator One of the distinct electronic/mechanical features is the red indicator flag. When the breaker trips, the handle moves to a center position, and a highly visible red window appears, allowing maintenance staff to quickly identify the faulted circuit. #### C. High Interrupt Capacity (22kA) The "VH" rating is critical for safety. It means the internal components (contacts and arc chutes) are reinforced to safely quench an electrical arc of up to 22,000 amps without the breaker exploding or failing to clear the fault. --- ### 4. Application and Compatibility The QO2125VH1200 is designed for use in **Square D QO Load Centers**, NQOD Panelboards, and Speed-D Switchboards. Due to its 125A rating, it is most commonly used as a **Main Breaker** for a small sub-panel or a **Feeder Breaker** for heavy machinery, HVAC units, or large EV charging stations.