<h2>Overview</h2>
<p>The <strong>Bussmann FRS-R-20</strong> is a 20-ampere, 600-volt dual-element time-delay fuse designed for reliable circuit protection in motor applications and industrial equipment. This lot includes three units rated for RK5 Class operation. The FRS-R series combines energy efficiency with current-limiting technology to protect sensitive electrical equipment from overloads and short circuits while allowing transient inrush currents to pass.</p>
<h2>Key Features</h2>
<ul>
<li><strong>Dual-Element Design:</strong> Provides both overload and short-circuit protection with response times as low as 0.004 second during fault conditions</li>
<li><strong>Time-Delay Technology:</strong> Allows motor startup inrush currents (10-second delay at 500% rated current) while protecting against sustained overloads</li>
<li><strong>High Interrupting Capacity:</strong> 200 kA at 600 VAC and 20 kA at 300 VDC per UL listing</li>
<li><strong>Class RK5 Rated:</strong> Meets UL current-limiting fuse standards for electrical equipment protection</li>
<li><strong>Ferrule End Design:</strong> Fits standard RK5 rejection-type fuse holders; can also be installed in Class H fuse blocks</li>
<li><strong>Energy Efficient:</strong> Reduces heat generation compared to standard fast-acting fuses</li>
</ul>
<h2>Technical Specifications</h2>
<ul>
<li><strong>Amperage Rating:</strong> 20 A</li>
<li><strong>Voltage Rating:</strong> 600 VAC / 300 VDC</li>
<li><strong>Fuse Class:</strong> RK5 (Class RK5)</li>
<li><strong>Fuse Type:</strong> Dual Element, Time Delay</li>
<li><strong>Interrupting Rating:</strong> 200 kA at 600 VAC; 20 kA at 300 VDC</li>
<li><strong>Time Delay Response:</strong> 10 seconds at 500% rated current</li>
<li><strong>Mounting Style:</strong> Ferrule End × Ferrule End (cartridge body)</li>
<li><strong>Dimensions:</strong> 0.81" diameter × 5" length</li>
<li><strong>Weight:</strong> 0.16 lbs per unit</li>
<li><strong>Material:</strong> Fiberglass tube with brass end caps</li>
<li><strong>Certifications:</strong> UL Listed</li>
<li><strong>Series:</strong> Fusetron FRS-R</li>
<li><strong>Quantity:</strong> Lot of 3 fuses</li>
</ul>
<h2>Typical Applications</h2>
<p>The Bussmann FRS-R-20 fuse is widely used in:</p>
<ul>
<li>Motor branch circuits and motor control centers</li>
<li>Transformer protection circuits</li>
<li>Industrial machinery and equipment with solenoid or inductive loads</li>
<li>Commercial HVAC and refrigeration systems</li>
<li>Combination motor starters and disconnect switches</li>
<li>Electrical distribution panels and switchgear rated up to 600 VAC</li>
</ul>
<h2>Compatibility & Replacements</h2>
<h3>Compatible With</h3>
<ul>
<li>RK5 Rejection-Type Fuse Holders</li>
<li>Class H Fuse Blocks (via groove/notch in end cap)</li>
<li>Class K Fuse Blocks</li>
<li>Class R Fuse Blocks</li>
<li>Combination Motor Starters</li>
<li>Industrial Control Equipment rated 600 VAC or less</li>
<li>General Purpose Distribution Panels</li>
</ul>
<h3>Replaces / Drop-In Replacement For</h3>
<ul>
<li>Bussmann FRS-20 (legacy part number variant)</li>
<li>Eaton Bussmann FRS-R-20 supersedes older Fusetron FRS series units</li>
<li>Cooper Bussmann 20A fuses in RK5 configuration</li>
</ul>
<h3>Works With</h3>
<ul>
<li>Standard AC electrical distribution systems (single-phase and three-phase)</li>
<li>DC systems rated up to 300 VDC</li>
<li>All UL-listed motor control and switchgear compatible with Class RK5 fuses</li>
</ul>
