Overview
The Bussmann LPS-RK-300 is an industrial-grade dual-element, time-delay fuse designed for critical circuit protection. As a Class RK1 fuse rated for 300 amps, it provides current-limiting performance and fast interrupting capability (300 kA at 600 Vac, 100 kA at 300 Vdc), making it ideal for feeder circuits, transformer protection, motor branch circuits, and general-purpose industrial applications where momentary inrush currents must be tolerated without nuisance trips.
Key Features
- Dual-element design: Time-delay response to accommodate inrush currents while providing fast short-circuit protection
- Class RK1 cartridge: Current-limiting fuse with blade-end connections for standard Class R fuse blocks
- High interrupting rating: 300 kA at 600 Vac; 100 kA at 300 Vdc
- Voltage compatibility: Rated for 600 VAC and 300 VDC systems
- Multiple certifications: UL, CSA, and CE approved for North American and international applications
Technical Specifications
Key dimensions and electrical parameters for system design and installation:
- Ampere Rating: 300 A
- Voltage Rating: 600 VAC / 300 VDC
- Fuse Class: RK1
- Type: Dual-element, time-delay, current-limiting
- Interrupting Rating: 300 kA (600 Vac); 100 kA (300 Vdc)
- Fuse Form Factor: Cartridge, blade-end
- Physical Length: 11 5/8 inches (279.4 mm)
- Weight: 3.4 lbs
Typical Applications
The Bussmann LPS-RK-300 excels in demanding industrial environments:
- Three-phase feeder and branch circuits in panels rated 300–600 A
- Transformer primary and secondary protection
- Motor branch circuits with high inrush demand
- Solenoid and contactor circuits
- General-purpose industrial distribution systems
- DC backup power and battery charger protection (at 300 VDC)
Compatibility & Replacements
Compatible With
- RM600 Class R fuse blocks (1-pole, 2-pole, 3-pole configurations)
- Class R fuse holder receptacles rated for 300 A operation
- 600 Vac / 300 Vdc industrial electrical distribution systems
- Single-phase and three-phase power panels
Replaces / Drop-In Replacement For
- LPS-RK-300SP (standard catalog designation)
- Legacy Bussmann LPS-RK 300A non-indicating fuses
- Other Class RK1, 300 A, time-delay fuses requiring identical ratings and form factor
Works With
- Class R fuse reducers (for equipment designed to accept smaller fuse case sizes)
- Standard industrial electrical single-line diagram design practices
- NFPA 70 (National Electrical Code) compliant installations
- IEC-rated switchgear and distribution equipment with Class R cavities
