The **FNQ-R-1/4** is a high-performance industrial fuse belonging to the **Limitron™** family. It is specifically designed as a "Class CC" fuse, which is a North American standard for small, space-saving fuses with high rejection capabilities. --- ## 1. Technical Specifications Below are the primary electrical and physical parameters for the FNQ-R-1/4: | Parameter | Specification | | :--- | :--- | | **Manufacturer** | Bussmann (by Eaton) | | **Amperage Rating** | 1/4 Amp (0.25A) | | **Voltage Rating (AC)** | 600 Vac | | **Interrupting Rating** | 200,000 Amps (200kA) RMS Sym. | | **Fuse Class** | Class CC | | **Time Characteristics** | Time-Delay (Slow Blow) | | **Physical Size** | 13/32" x 1-1/2" (10.3 x 38.1 mm) | | **Body Material** | Melamine Tube | --- ## 2. Key Electronic Features ### A. Time-Delay Characteristic Unlike "Fast-Acting" fuses, the FNQ-R-1/4 is designed with a **Time-Delay** feature. This allows the fuse to withstand temporary surge currents (such as motor startup or transformer inrush) without blowing, while still providing reliable protection against sustained overloads and short circuits. ### B. Current Limitation The FNQ-R-1/4 is highly **Current-Limiting**. In the event of a massive short circuit, the fuse reacts fast enough to stop the current flow before it reaches its full peak, significantly reducing the "let-through" energy that could damage downstream components. ### C. Rejection Feature As a **Class CC** fuse, it features a physical "rejection tip" on one end. This ensures that: 1. It can only be inserted into a Class CC fuse holder. 2. It prevents a user from accidentally replacing it with a lower-rated fuse (like a standard midget fuse) that lacks the same interrupting capacity. --- ## 3. Typical Applications Because of its 1/4 Amp rating and time-delay nature, this fuse is commonly found in the following electronic and electrical environments: * **Control Transformers:** Protecting the primary side of small control power transformers. * **Solenoids and Inductive Loads:** Circuits that experience high momentary "inrush" currents. * **Industrial Control Panels (ICP):** Used where space is limited but high interrupt ratings (200kA) are required by code. * **Branch Circuit Protection:** Specific applications requiring specialized Class CC protection. --- ## 4. Comparison: FNQ-R vs. FNQ It is important not to confuse the **FNQ-R** with the standard **FNQ** series: * **FNQ-R (Class CC):** Has the rejection tip, 200kA interrupting rating, and is branch-circuit rated. * **FNQ (Midget):** No rejection tip, lower interrupting rating (usually 10kA), and is intended for supplemental protection only.