Overview
The Bussmann FRS-R-20 Fusetron Class RK5 fuse is a dual-element, time-delay, current-limiting fuse designed for branch circuit and industrial motor control applications. Rated 20A at 600V AC / 300V DC, this cartridge-style fuse combines fast short-circuit protection with deliberate overload tolerance, making it ideal for equipment that draws legitimate inrush current. The FRS-R series offers selective coordination within the RK5 fuse family, reducing nuisance outages and protecting only the failed circuit.
Key Features
- Dual-Element Time-Delay Construction — 10 second minimum at 500% rated current prevents nuisance trips during motor startup or transformer energization
- Current-Limiting Performance — 200 kA interrupting rating at 600V AC and 20 kA at 300V DC
- Class RK5 UL Listed — meets CSA C22.2 No. 248.12 and UL standards for cartridge fuses
- Selective Coordination — 2:1 selective coordination ratio within RK5 fuse family prevents electrical shutdowns from extending beyond the failed circuit
- Non-Indicating Design — standard non-indicating element (optional indication available on select ratings)
- Compact Cartridge Form — 0.81″ × 5.00″ dimensions fit standard Class R fuse blocks
Technical Specifications
| Rating | 20A |
| Voltage | 600V AC / 300V DC |
| Class | RK5 (Class R) |
| Type | Dual-Element, Time-Delay, Current-Limiting |
| Interrupting Capacity | 200 kA at 600V AC; 20 kA at 300V DC |
| Time-Delay at 500% Rated Current | 10 seconds (minimum) |
| Dimensions | 0.81″ (±0.008) diameter × 5.0″ (±0.031) length |
| Form Factor | Cartridge Fuse (Class R Rejection Type) |
| Series | Fusetron FRS-R |
| Manufacturer | Eaton / Bussmann Series |
| Certifications | UL Listed, CSA C22.2 No. 248.12 |
Typical Applications
- Motor control centers (MCC) and branch circuit protection
- Industrial machinery and automation equipment
- HVAC, pump, and compressor motor circuits
- Transformer and capacitor bank protection
- Control panel distribution systems in manufacturing plants
Compatibility & Replacements
Compatible With
- Class R fuse blocks and holders (standard 600V cartridge configuration)
- Recommended for RM60030 and RM60060 series fuse blocks
- Any equipment rated for Class RK5, 600V cartridge fuses
- Industrial control systems and motor starter circuits
Replaces / Drop-In Replacement For
- Cooper Bussmann FRS-R-20
- Eaton Bussmann FRS-R-20
- Other brand Class RK5 20A fuses of the same physical cartridge dimensions
Works With
- Class R fuse blocks and cartridge holders
- Standard 600V distribution equipment
- Motor control circuits requiring selective coordination
- Any AC/DC system rated for Class RK5 protection
