Overview
The Bussmann FRS-R-1 is a Class RK5 Fusetronâ„¢ dual-element, time-delay fuse designed for reliable overcurrent protection in industrial automation and control systems. Manufactured by Eaton Bussmann, this 1 Amp fuse combines a separate overload element with a short-circuit element to deliver both overload tolerance and fast short-circuit response. Rated at 600 Vac and 300 Vdc with a 200 kA interrupting rating, the FRS-R-1 meets UL and CSA standards for branch-circuit applications in motor circuits, control panels, and electrical distribution equipment.
Key Features
- Dual-Element Time-Delay Design — Separate overload and short-circuit elements allow sizing as close as 125% of motor Full Load Amps (FLA) while maintaining excellent short-circuit protection
- Current-Limiting Technology — Reduces let-through current and heat generation during fault conditions, protecting downstream equipment from damage
- 10-Second Time-Delay — Minimum 10 seconds at 500% rated current tolerates motor inrush and temporary overloads without nuisance trips
- 200 kA Interrupting Rating — Rated for high fault currents up to 200,000 Amps RMS symmetrical at 600 Vac and 20 kA at 300 Vdc
- Non-Indicating Design — Fuse end caps remain fully insulated; blown fuses must be visually inspected or circuit tested
- UL and CSA Certified — Complies with UL and Canadian Standards Group (CSA) Class RK5 branch-circuit fuse standards
Technical Specifications
| Nominal Amperage | 1 A |
| Voltage Rating | 600 Vac / 300 Vdc |
| Interrupting Rating | 200 kA at 600 Vac; 20 kA at 300 Vdc |
| Fuse Class | RK5 (Fusetronâ„¢) |
| Type | Dual-Element, Time-Delay, Current-Limiting |
| Time-Delay Performance | 10 seconds (minimum) at 500% rated current |
| Indication | Non-Indicating |
| Physical Size | 5″ length × 0.81″ diameter (±0.008″) |
| Thermal Time-Current Curve | Available in datasheet no. 1017 |
| Standards | UL 248.12, CSA C22.2 No. 248.12 |
| Manufacturer | Eaton Bussmann Series |
| Compatible Fuse Block Series | RM60030, RM60060 (Class RK5) |
Typical Applications
- Motor Circuits — Provides overload tolerance with short-circuit protection for AC induction motors in industrial equipment
- Control Panel Protection — Protects branch circuits, transformers, and control systems in machine control cabinets
- Industrial Automation — Ideal for PLC, drive, and HMI feeder circuits in manufacturing automation systems
- Distribution Equipment — Suitable for disconnect switches, combination starters, and motor control centers
- Selective Coordination — 2:1 selective coordination ratio with other Class RK5 Bussmann fuses prevents upstream fuse operation
Compatibility & Replacements
Compatible With
- Class RK5 fuse holders and clips (Bussmann RM60 series fuse blocks)
- Motor control centers and combination starters rated for Class R fuses
- Industrial control panels and electrical distribution equipment
- Single-phase and three-phase 600 Vac circuits
- 310 Vdc and below DC applications (300 Vdc rating)
Replaces / Drop-In Replacement For
- Other Bussmann FRS-R-1 fuses (pin-for-pin compatible Class RK5 cartridges)
- OEM-equivalent Class RK5 dual-element fuses where part specifications match
Works With
- Bussmann Class RK5 fuse reducer blocks (for oversized fuse holders)
- Class R fuse clips and terminals in 600 Vac distribution systems
- Industrial motor starters and soft-start controllers
- Variable frequency drives (VFDs) in applications with 600 Vac main feeder protection
- Selective coordination with other Class RK5 Fusetron products within the Bussmann series
