Eaton Bussmann frn-r-125 Class RK5 Fuse 125A

Product Description

The EATON BUSSMANN frn-r-125 is a Class RK5, dual-element, time-delay, current-limiting fuse rated at 125 amps for use in AC and DC power distribution systems. It carries an interrupting rating of 200 kA at 250 Vac and 20 kA at 125 Vdc, making it suitable for circuits where high fault currents are a concern. The dual-element construction provides true time-delay performance, allowing motor inrush currents to pass without nuisance opening while still providing fast response to sustained overloads and short circuits. Electricians and industrial maintenance technicians install this fuse in disconnect switches, motor starters, feeder circuits, and branch circuit protection panels.

This fuse is appropriate for residential, commercial, and light industrial applications where Class RK5 protection is specified. Common install scenarios include motor branch circuits requiring overload and short-circuit protection, HVAC equipment disconnects, and feeder panels where current-limiting performance is required by code. The time-delay characteristic makes it well suited for motor loads that draw high inrush current at startup without triggering an overcurrent event.

Key Features

• 125-amp continuous current rating for motor and feeder circuit protection
• Dual-element construction delivers true time-delay performance for motor inrush tolerance
• Current-limiting design reduces let-through energy during fault conditions
• Interrupting rating of 200 kA at 250 Vac for high-fault-current environments
• Rated for DC applications at 20 kA interrupting capacity at 125 Vdc
• Non-indicating design with Class RK5 classification

Compatibility

Designed as an OEM-style replacement Class RK5 fuse for use in standard RK5-rated fuse holders and disconnect switches that accept 250 Vac time-delay fuses in the 125-amp range.

Installation Notes

Installation should be performed by a licensed electrician in accordance with NEC Article 240 and applicable local codes. Always de-energize and lock out the circuit before replacing a fuse. Verify that the fuse holder is rated for Class RK5 fuses and matches the voltage and amperage of the replacement before installation. Do not install this fuse in a holder rated below 250 Vac or in a circuit exceeding the published interrupting rating.

Technical Specifications

• Current Rating: 125 amps
• Voltage Rating (AC): 250 Vac
• Voltage Rating (DC): 125 Vdc
• Interrupting Rating (AC): 200 kA at 250 Vac
• Interrupting Rating (DC): 20 kA at 125 Vdc
• Fuse Class: RK5
• Fuse Series: FRN-R
• Element Type: Dual-element, time-delay
• Current Limiting: Yes
• Indicating: Non-indicating

Standard Information

• Brand: EATON BUSSMANN
• Manufacturer Part Number: frn-r-125