The **HTB-28M-R** is a high-performance, panel-mount fuse holder manufactured by **Eaton (formerly Bussmann)**. It is specifically designed for 5mm x 20mm fuses and is widely used in industrial and commercial electronic equipment to provide overcurrent protection. Below is a detailed breakdown of its electronic and mechanical specifications. ### 1. Technical Specifications | Feature | Specification | | :--- | :--- | | **Part Number** | HTB-28M-R | | **Fuse Size Accepted** | 5mm x 20mm | | **Current Rating** | 16 Amps (UL) / 6.3 Amps (VDE) | | **Voltage Rating** | 250 Volts AC | | **Mounting Type** | Panel Mount (Snap-in) | | **Terminal Type** | 3/16" Quick Connect / Solder Terminals | | **Knob Type** | Screwdriver Slot (Low Profile) | | **Body Material** | High-temperature thermoplastic | --- ### 2. Key Electronic Components & Design #### A. Contact Construction The internal contacts are typically made of **tin-plated brass**. This ensures low electrical resistance and prevents oxidation, which is critical for maintaining a stable connection under high current loads. #### B. Terminal Configuration The "28" in the part number signifies the terminal style. The HTB-28M-R features **right-angle terminals**. This is particularly useful in shallow enclosures where vertical space is limited, allowing wires to be connected parallel to the panel surface. #### C. Insulation Resistance The thermoplastic body is designed to withstand high dielectric voltages (typically up to 1500V AC). This prevents electrical "arcing" between the fuse contacts and the metal chassis of the device. --- ### 3. Physical & Mechanical Features * **Snap-in Mounting:** Unlike threaded fuse holders that require a nut, the HTB-28M-R snaps directly into a standard 0.5-inch D-shaped hole. This reduces assembly time in manufacturing. * **Low Profile Knob:** The "M" in the suffix indicates a screwdriver-release knob. This prevents accidental removal of the fuse by hand, adding a layer of safety for the end-user. * **Environmental Resilience:** The materials are rated for wide temperature ranges, typically from **-40°C to +85°C**. --- ### 4. Wiring Diagram (Simplified) ```text [Line In] ----> [Internal Contact] ----> [Fuse] ----> [Load Contact] ----> [Load] | | (Right-Angle Terminal) (Right-Angle Terminal) ``` ---