Overview
The Bussmann FRS-R-20 Fusetron is a dual-element, time-delay Class RK5 fuse rated for 20 amperes at 600 volts AC (or 300 volts DC). This current-limiting cartridge fuse is engineered for motor control and branch circuit protection in industrial automation, machinery disconnects, power panelboards, and combination starter applications. The time-delay characteristic provides selective coordination within the RK5 family, preventing nuisance shutdowns on momentary inrush currents while protecting against sustained faults.
Key Features
- Dual-element, time-delay design — provides coordinated protection against short circuits and overloads
- Class RK5 current-limiting — reduces let-through current and stress on downstream equipment
- Non-indicating style — does not have a visual blown-fuse indicator
- Brass end caps and fiberglass tube — durable construction suitable for harsh industrial environments
- 2:1 selective coordination — prevents electrical shutdowns from extending beyond the failed circuit
Technical Specifications
- Amperage: 20 A
- Voltage Rating (AC): 600 Vac
- Voltage Rating (DC): 300 Vdc
- Fuse Class: RK5
- Type: Dual-element, time-delay, non-indicating
- Interrupting Rating: 200 kA RMS symmetrical @ 600 Vac; 20 kA @ 300 Vdc
- Dimensions: 0.81″ diameter × 5.0″ length
- Connection: Ferrule end contacts
- Certifications: UL Listed (Guide JDDZ, File E4273); CSA Certified (Class 1422-01, File 53787)
Typical Applications
The FRS-R-20 is ideal for:
- Motor control centers and motor starter circuits
- Combination starters and machinery disconnects
- Industrial control panel and branch circuit protection
- Power distribution in manufacturing and automation facilities
- Equipment requiring coordinated, current-limiting short-circuit protection
Compatibility & Replacements
Compatible With
- Standard Class RK5 fuse clips and fuse blocks rated 20 A, 600 V
- Industrial motor control equipment and starters
- Combination starter circuits
- Power panelboards and distribution centers
- Any circuit requiring selective coordination within RK5 fuse family
Replaces / Drop-In Replacement For
The FRS-R-20 is directly compatible with the Fusetron FRS-R-20 product line. Verify compatibility with your specific fuse block or holder before installation to ensure proper ferrule-end contact fit.
Works With
- Bussmann and Eaton fuse blocks (RM60030 and RM60060 series recommended for Class R fuses)
- Class R fuse reducers (NO.663-R for 30/60 A reduction, NO.216-R for 30/100 A reduction)
- Standard industrial electrical enclosures and control panels
- Allen-Bradley, Siemens, GE, and other major automation control systems
