Overview
The Bussmann FRS-R-20 is a Class RK5 dual-element, time-delay cartridge fuse engineered for reliable circuit protection in industrial and commercial applications. Rated 20 A with an interrupting rating of 200 kA at 600 Vac and 20 kA at 300 Vdc, this fuse combines energy-efficient performance with superior inrush tolerance for motor startup and transformer energization scenarios.
Key Features
- Dual-element, time-delay design with 10 second (minimum) at 500% rated current; 200,000A Interrupting Rating
- Ferrule-end x ferrule-end mounting, 5″ length × 0.81″ diameter cartridge
- UL Class RK5 Fusetron with energy efficient advanced protection
- Suitable for use in various fuse blocks and equipment requiring UL current limiting protection
- Dual-element construction prevents nuisance blowing during motor inrush and soft-start transients
Technical Specifications
The following specifications are derived from manufacturer and distributor documentation:
- Amperage: 20 A
- Voltage Rating: 600 Vac / 300 Vdc
- Interrupt Rating: 200 kA at 600 Vac, 20 kA at 300 Vdc
- Fuse Type: Dual Element, Time Delay
- Class: RK5
- Response Time: 10 seconds at 500% rated current
- Mounting: Ferrule End x Ferrule End
- Series: FRS-R
- Physical Size: 0.81″ Dia x 5″ L (20.57x127mm)
- Weight: 3.2 oz
- Certifications: UL, CSA, CE
Typical Applications
The FRS-R-20 is well-suited for:
- Motor branch circuits and motor protection
- Transformer inrush current scenarios
- Industrial control panels and distribution equipment
- HVAC compressor and pump circuits
- Equipment requiring RK5 current-limiting protection
Compatibility & Replacements
Compatible With
- Standard ferrule-mount fuse blocks and holders rated for Class RK5 fuses
- Industrial control panels and motor control centers (MCCs)
- Electrical distribution equipment operating at 600V AC or 300V DC
- Motor soft-starters and variable frequency drives (VFDs) requiring fused disconnect
Replaces / Drop-In Replacement For
- Other Bussmann FRS-R series 20A fuses
- Cooper Bussmann FRS-R-20 (legacy designation)
- Verify exact compatibility with your equipment manufacturer before substitution
Works With
- Class RK5 ferrule-end fuse blocks and bayonet holders
- UL/CSA-rated motor control centers (MCCs)
- Industrial power distribution panels
- Equipment designed for dual-element, time-delay fuses
