Overview
Bussmann LPJ-50SP is a Low-Peak® Class J dual-element, current-limiting time-delay fuse rated 600VAC/300VDC at 50 amps. The LPJ-50SP provides ultimate protection class-J current-limiting with non-indicating design, making it ideal for applications requiring selective coordination and overload tolerance. Current-limitation protects downstream components against damaging thermal and magnetic effects of short-circuit currents.
Key Features
- Dual-Element Design: Long time-delay minimizes needless fuse openings due to temporary overloads and transient surges, while dual-element fuses have lower resistance than ordinary fuses so they run cooler.
- Class J Current Limiting: Provides fast current interruption to minimize fault damage and protect sensitive downstream equipment.
- Time-Delay Protection: 10 seconds minimum at 500% of rated current allows inrush currents without unnecessary nuisance blowing.
- Selective Coordination: Consistent 2:1 ampacity ratios make selective coordination easy, enabling coordinated protection strategies across multi-level circuits.
- Certifications: UL Listed and CSA Certified for North American industrial standards.
Technical Specifications
- Amperage Rating: 50A
- Voltage Rating: 600VAC / 300VDC
- Fuse Class: J (Class J per UL 248-8 and CSA C22.2 No. 248.8)
- Type: Time-Delay, Non-Indicating, Dual-Element Current-Limiting
- Interrupting Rating: 300,000 A (300 kA) at 600 VAC and 100,000 A at 300 VDC
- Time-Delay Response: 10 seconds (minimum) at 500% of rated current
- Connection: Ferrule Terminal (ferrule end × ferrule end)
- Body Style: Cylindrical
- Dimensions: 1.06 in Dia × 2.38 in L (26.92 × 60.45 mm)
- Material: Melamine body
- Weight: 3.2 oz (per unit)
- Approvals: CE, UL, CSA, RoHS
Typical Applications
- Branch circuit breaker panelboard mains protection
- Industrial control circuit protection and motor starter circuits
- Machinery disconnects and power distribution systems
- Backup protection against motor burnout from overload or single phasing; provides no-damage type-2 coordinated protection for NEMA and IEC motor controllers
- High-inrush applications requiring coordinated time-delay fusing
Compatibility & Replacements
Compatible With
- Eaton Bussmann Low-Peak® series fuse holders and blocks rated for Class J
- Branch circuit panels designed for Class J fuses at 600V
- Industrial control systems and NEMA/IEC motor starters
- Power distribution equipment rated 600VAC or lower
Replaces / Drop-In Replacement For
- LPJ50, LPJ 50 Amp, LPJ-50, LPJ 50A, LPJ50A, LPJ-50A, LPJ 50, LPJ50SP, LPJ50-SP, LPJ-50-SP (alternate part number designations)
- Cooper Bussmann LPJ-50SP legacy stock
- Other Class J 50A 600V time-delay fuses with equivalent 300kA interrupt rating (verify holder compatibility before substitution)
Works With
- Bussmann Low-Peak® series Class J fuse accessories and holder blocks
- Any Class J fuse holder or blade block rated 600V and 50A minimum
- Industrial automation control systems and motor protection circuits
- UL and CSA approved power distribution systems
