Bussmann Time Delay Fuse FRN-R Series 125A 250VAC/125VDC Class RK5 Dual Element Blade End

Bussmann Time Delay Fuse FRN-R Series 125A 250VAC/125VDC Class RK5 Dual Element Blade End

Professional-Grade Motor and Transformer Circuit Protection

The Bussmann Time Delay Fuse FRN-R Series 125A delivers superior electrical protection and circuit safety for motor circuits, transformers, and high-inrush applications. This Class RK5 time delay fuse features dual element current limiting technology designed for electrical contractors, industrial facilities, and commercial installations, providing the reliable overcurrent protection and industry-leading safety that electrical professionals demand.

Professional Features & Benefits

Advanced Time Delay Protection

• Dual Element Design - Provides time delay on overloads while offering fast clearing on short circuits for optimal motor protection
• 10 Second Time Delay at 500% - Allows motor starting currents and temporary overloads while protecting against sustained overcurrent conditions
• 125A Current Rating - Handles high-capacity electrical loads with reliable overcurrent protection for industrial applications
• Current Limiting Technology - Reduces let-through energy and peak current to protect downstream equipment and enhance system safety

Safety & Standards Compliance

• Class RK5 Classification - Meets NEC requirements for motor circuit protection with proven electrical safety performance
• 200 kAIC Interrupt Rating at 250VAC - Provides exceptional fault current clearing capability for industrial and commercial electrical systems
• CE Marked Compliance - Ensures international electrical safety standards for global installations and regulatory compliance

Technical Specifications

125A amperage rating, 250VAC/125VDC voltage rating, 200 kAIC interrupt rating at 250VAC, Class RK5 fuse classification, dual element construction, blade end x blade end connection, 10 second time delay at 500% rated current, 2.1" length x 0.54" width x 0.54" height dimensions, 0.5 lb weight, non-indicating design for standard electrical panel installations.

Installation & Setup

1. Verify electrical system is de-energized and follow proper lockout/tagout procedures for safe fuse installation
2. Confirm fuse holder compatibility with blade end connection type and Class RK5 dimensional requirements
3. Insert fuse into holder ensuring proper blade contact alignment and secure mechanical connection
4. Verify amperage rating matches circuit protection requirements and motor full load current specifications
5. Test circuit operation and confirm proper overcurrent protection functionality before energizing equipment
6. Document installation details including fuse specifications and installation date for maintenance records

Professional Applications

Ideal for:

• Motor Protection Circuits - HVAC motors, pump motors, compressor motors, and industrial machinery requiring time delay protection
• Transformer Primary Protection - Distribution transformers, control transformers, and power supply transformers in commercial facilities
• Industrial Control Panels - Motor control centers, variable frequency drives, and automated equipment protection systems
• Commercial Lighting Circuits - High-intensity discharge lighting, LED drivers, and ballast protection applications
• Power Distribution Systems - Electrical panels, switchgear, and distribution boards requiring reliable overcurrent protection
• HVAC Equipment Protection - Air handling units, chillers, boilers, and building automation system electrical protection
• Manufacturing Equipment - Production machinery, conveyor systems, and process equipment electrical safety
• Electrical Service Panels - Main panels, sub-panels, and load centers in industrial and commercial installations

Dual Element Current Limiting Advantage

Bussmann dual element technology combines time delay overload protection with fast-acting short circuit protection, providing superior motor circuit safety. The current limiting design reduces arc energy and system stress during fault conditions, while the time delay element prevents nuisance tripping during motor starting and temporary overload conditions, ensuring reliable electrical system operation.

Why Choose Bussmann Quality?

Bussmann demonstrates unwavering commitment to electrical safety through rigorous testing, NEC compliance, and proven overcurrent protection technology. Our Class RK5 time delay fuses provide reliable motor protection, current limiting performance, and electrical system safety for professional installations, backed by decades of electrical protection innovation and industry-leading quality standards.