Overview
The Bussmann LPJ-4SP is a Class J low-peak time-delay fuse designed for demanding industrial and commercial electrical systems. As part of the Bussmann Low-Peak family, this dual-element fuse combines overload protection with short-circuit current limitation in a compact form factor. The 4-amp rating at 600 Vac makes it suitable for branch circuits and motor protection in control cabinets, machinery, and automation systems where high inrush currents are common.
Key Features
- Dual-Element Design: Separate overload and short-circuit elements enable time-delay characteristics ideal for motor inrush currents
- 300 kA Interrupting Rating: High breaking capacity at 600 Vac RMS Symmetrical, 100 kA at 300 Vdc
- 10-Second Ride-Through: Tolerates 500% of rated current for minimum 10 seconds, perfect for high-inrush loads
- Class J Standard Compliance: UL 248-8 and CSA C22.2 No. 248.8 certified for industrial applications
- Ferrule Terminal Connection: Secure contact design ensures reliable performance in fuse blocks and holders
- Selective Coordination: 2:1 coordination ratio within Low-Peak family prevents widespread shutdowns during faults
Technical Specifications
| Current Rating | 4 Amperes |
| Voltage Rating (AC) | 600 Vac RMS |
| Voltage Rating (DC) | 300 Vdc |
| Interrupting Rating (AC) | 300,000 A at 600 Vac |
| Interrupting Rating (DC) | 100,000 A at 300 Vdc |
| Fuse Class | Class J |
| Type | Time-Delay (Dual-Element, Current-Limiting) |
| Time-Delay Performance | Minimum 10 seconds at 500% rated current |
| Terminal Type | Ferrule |
| UL File Number | JDDZ.E4273 |
| Certifications | UL 248-8, CSA C22.2 No. 248.8, CE, RoHS Compliant |
| Package Quantity | Box of 6 |
Typical Applications
- Motor branch-circuit protection in industrial machinery
- Control cabinet and panel protection in automation systems
- High-inrush load protection (HVAC compressors, large pump motors)
- Machine tool circuits requiring selective coordination
- General industrial process equipment
- Commercial elevator and escalator control systems
Compatibility & Replacements
Compatible With
- Class J fuse blocks and holders (standard receptacle design)
- Industrial control panels rated for 600 Vac
- Motor starters and soft-start controllers
- Variable frequency drives (VFD) branch circuits
- Industrial automation cabinets and enclosures
- Power distribution equipment rated 600 V and below
Replaces / Drop-In Replacement For
- Other Class J fuses of identical amp rating (verify physical dimensions and terminal type)
- Legacy fuse installations requiring upgrade to Low-Peak performance
- Verify compatibility with your system integrator before ordering
Works With
- Class J fuse blocks (all manufacturers: Eaton, Siemens, ABB, Schneider Electric, others)
- 600 Vac and 300 Vdc electrical systems
- Industrial motor control centers and MCC equipment
- UL 248-8 and CSA C22.2 compliant distribution systems
- Selective coordination applications within the Low-Peak family (2:1 ratio)
