Overview
The Cooper Bussmann FRS-R-50 is a Fusetron Class RK5 dual-element, time-delay fuse designed for circuit protection in industrial and commercial applications. This fuse features ferrule end connections, 50A rating, 600V AC / 300V DC, with a 1.06-inch diameter and 5.50-inch overall length. It provides a 200,000A interrupting rating with 10-second minimum response time at 500% rated current, making it suitable for protecting motors, transformers, and other equipment against overloads and short circuits.
Key Features
- Dual-element, time-delay construction provides energy-efficient advanced protection
- 10-second minimum time delay at 500% rated amps — prevents nuisance trips on temporary motor surges
- RK5 Class rejection-type with ferrule terminal design
- Current-limiting technology reduces arc flash hazard
- Provides motor overload, ground fault, and short-circuit protection in one device
- Closer sizing flexibility allows use of smaller switches and lower system cost
Technical Specifications
Typical Applications
The FRS-R-50 is widely used in:
- Motor control circuits and motor branch protection
- Transformer primary and secondary protection
- Industrial distribution panels and switchboards
- HVAC equipment and machinery circuits rated 50A at 600V
- Manufacturing facilities and process control systems requiring dual-element protection
Compatibility & Replacements
Compatible With
- Class RK5 fuse holders and rejection-type clip holders
- Standard 600V AC / 300V DC electrical distribution systems
- Motor starters, disconnect switches, and panelboards rated for 50A circuits
- Any industrial control system requiring 50-amp circuit protection
Replaces / Drop-In Replacement For
- Previous Cooper Bussmann FRS-R-50 fuses
- Verify compatibility with your system integrator before ordering when replacing other Class RK5 50A fuses
Works With
- Standard electrical distribution switchgear and panelboards
- Motor control centers (MCCs) with Class RK5 rejection-type fuse clips
- Industrial automation control systems requiring branch circuit protection
- Power distribution equipment rated for 600V AC service












