FRN-R-30
30A 250V Class RK5 dual-element time-delay fuse specifically designed for motor circuit protection with excellent sta...
Product Overview
Description
The FRN-R-30 is a dual-element time-delay fuse designed specifically for motor circuit protection.
With 250V rating and 30A current capacity, this fuse handles motor starting currents without nuisance opening.
The RK5 design provides excellent protection with superior time-delay characteristics.
Product Series
FRN
Primary Application
Motor circuit protection
Key Features
- 250V rating for motor circuits
- Dual-element time-delay design
- Handles motor starting currents
- Excellent for combination motor/feeders
- UL Listed and CSA Certified
- Economical motor protection
Specifications
| Voltage Rating | 250V AC |
|---|---|
| Current Rating | 30A |
| Breaking Capacity | 10kA AC |
| Class | RK5 |
| Time-Current | Dual-element time-delay |
| Size | Standard RK size |
| Standards | UL 248-12, CSA C22.2 |
Applications
Motor circuit protection
Motor drive and control systems
Combination motor feeders
Motor drive and control systems
Motor disconnect switches
Motor drive and control systems
Industrial motors
Motor drive and control systems
Pumps and compressors
Electronic system design
HVAC motors
Motor drive and control systems
FAE Expert Insights
"The FRN-R series has been the standard for motor protection for decades. The dual-element design handles motor starting currents beautifully - typically 500% of rated current for 10-20 seconds without opening. This is essential for across-the-line motor starting. For motor circuits, the combination of time-delay fuse and motor starter overloads provides comprehensive protection. The RK5 class offers an economical choice while still providing adequate current limitation. I've seen these fuses reliably protect motors for many years in harsh industrial environments. I recommend sizing at 125-150% of motor FLA for optimal protection."
Economical and reliable motor protection with excellent time-delay characteristics
— Michael Wang, BeiLuo
Frequently Asked Questions
What size fuse should I use for motor protection?
Motor fuse sizing: Size at 125-175% of motor full-load current depending on NEC code and motor type. For example: 10HP motor at 230V = 28A FLA, use 35A or 40A fuse (125-140%). Always verify with motor nameplate and NEC requirements.
Size at 125-175% of FLA. Consult NEC for specific requirements.
How does the time-delay feature work?
The dual-element design has a heat sink element that absorbs energy during temporary overloads like motor starting. This allows 500-600% of rated current for 10-20 seconds without opening. The short-circuit element opens quickly on severe faults.
Use time-delay fuses for any circuit with motor starting or transformer inrush.
What is the difference between RK1 and RK5?
RK1 provides the highest current limitation with superior arc flash reduction. RK5 offers economical protection with good time-delay but lower current limitation. For critical applications, RK1 is preferred.
Use RK1 for superior protection. Use RK5 for economical general motor protection.
Can I use this fuse for 480V systems?
No, the FRN-R-30 is rated for 250V AC. For 480V systems, use FRN-R-30 fuses with 600V rating (FRS-R series) or Class J fuses rated for 600V. For detailed specifications and application support on bussmann FRN-R-30, refer to the datasheet or contact our team.
Verify voltage rating matches your system. Use 600V rated fuses for 480V systems.
What is the typical lifespan of this fuse?
Under normal conditions, fuses last many years. However, each overload event causes minor aging. Motors with frequent starting may require more frequent fuse inspection. Replace fuses that show signs of heating or damage.
Inspect fuses annually. Replace if showing signs of heating or after severe fault events.