Overview
The Bussmann FRS-R-400 is a Fusetron dual-element, time-delay fuse rated for 400A at 600Vac/300Vdc. This Class RK5 cartridge fuse combines current-limiting and time-delay protection in a single compact component, making it ideal for motor circuits and industrial control systems where temporary surge currents must be tolerated without nuisance trips.
Key Features
- Dual-element construction for true time-delay response at motor inrush
- Class RK5 current-limiting characteristics reduce fault stresses on equipment
- Operates at 10 seconds minimum delay at 500% of rated current
- 200 kA RMS symmetrical interrupting rating at 600V; 20 kA at 300V DC
- Non-indicating cartridge body with blade terminals for standard fuse blocks
- UL 248-12 and CSA C22.2 No. 248.12 certified
Technical Specifications
- Rated Current: 400A
- Voltage Rating: 600Vac / 300Vdc
- Class: RK5
- Fuse Type: Time-Delay, Dual-Element
- Body Style: Cartridge
- Interrupting Rating: 200 kA @ 600Vac; 20 kA @ 300Vdc
- Time-Delay Response: 10 seconds minimum at 500% rated current
- Dimensions: 2.34 in. diameter × 11.63 in. length (225–400A size)
- Terminal Type: Blade (Knife) Terminal
- Certifications: cULus Listed (UL File No. JDDZ.E4273)
- Manufacturer: Eaton Bussmann
Typical Applications
The FRS-R-400 is commonly used in:
- Motor branch circuits and motor control centers requiring time-delay coordination
- Transformer circuits subject to inductive surge currents
- Industrial automation and machinery control systems operating at 600V
- Large HVAC compressor and pump applications
- Power distribution systems where selective coordination is required
Compatibility & Replacements
Compatible With
- Eaton/Bussmann RM60400 and RM60600 series 600V fuse blocks (225–600A ratings)
- Standard Class RK5 fuse holders rated for 600V operation
- Motor control centers and industrial panelboards with 600V cartridge fuse provisions
- Circuits requiring UL 248-12 Class RK5 fuse protection
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. The FRS-R-400 is a direct replacement for older Fusetron 400A 600V time-delay cartridge fuses in the same size envelope; however, confirm fuse block compatibility before installation.
Works With
- Motor Protection Circuits – provides coordinated overload and short-circuit protection
- Industrial Automation Networks – compatible with standard 600V panel designs and control systems
- Power Distribution – integrates into utility and facility power systems using Class RK5 fuse coordination
- Transformer Protection – suitable for circuits with magnetizing inrush typical of power transformers
