Overview
The FRS-R-4 fuse from Cooper Bussmann (Eaton Bussmann) is a Class RK5 cartridge fuse engineered for branch-circuit and equipment protection in industrial and commercial applications. This dual element time delay fuse is rated 4A at 600VAC/300VDC with a 200kA interrupting rating at 600VAC and 20kA at 300VDC. Built with a current-limiting design and 10 second time delay characteristics, the FRS-R-4 prevents nuisance trips while protecting sensitive equipment from overload and short-circuit conditions.
Key Features
- Dual Element Design: Time delay characteristics provide 2:1 selective coordination ratio within the RK5 fuse family, preventing electrical shutdowns from extending beyond the failed circuit
- Current Limiting: High interrupting rating of 200 kiloampere at 600Vac limits fault current and minimizes equipment damage
- Cartridge Body: Standardized 0.81″ diameter × 5.00″ length with ferrule terminals for clip-mount holders
- No Indicator: Non-indicating design for simple, cost-effective installations
- Industry Standards: UL 248-12, CSA, and CE approved
Technical Specifications
- Rated Current: 4 amperes
- Voltage Rating: 600 VAC / 300 VDC
- Fuse Class: Class RK5
- Type: Dual element, time delay (slow blow)
- Interrupting Rating: 200 kA @ 600VAC, 20 kA @ 300VDC
- Time Delay: 10 seconds at 500% rated load
- Body Style: Cartridge
- Diameter: 0.81 inches (20.6 mm)
- Length: 5.00 inches (127 mm)
- Termination: Ferrule clips
- Indicator: Non-indicating
- Approvals: UL, CSA, CE
- Brand: Fusetron (Bussmann series)
Typical Applications
FRS series fuses without indicator provide excellent protection for all types of circuits. Common uses include:
- Industrial machine tool protection
- HVAC systems and motor circuits
- Control transformer circuits
- Branch circuits requiring selective coordination
- Semiconductor equipment and data center power distribution
Compatibility & Replacements
Compatible With
- Class RK5 fuse holders and clips
- 680-volt and lower AC distribution systems
- 300 VDC applications
- Standard North American industrial control panels
Replaces / Drop-In Replacement For
- Previous generation Fusetron FRS-R-4 cartridges
- Comparable Class RK5 4-ampere time-delay fuses
- Systems designed for RK5 fuse selectivity
Works With
- Class RK5 fuse-clip assemblies and cartridge holders
- Switchboards, panelboards, and motor control centers (MCCs)
- NEMA-compliant branch-circuit protection schemes
- Any circuit rated for RK5 current-limiting protection
