Littelfuse KLNR125 RK1 Fuse 125A 250V

Product Description

The LITTELFUSE KLNR125 is a Class RK1 time-delay fuse rated at 125 amps and 250 volts. Class RK1 fuses provide a high degree of current-limiting protection, offering superior fault clearing compared to standard Class K fuses. The time-delay characteristic allows the fuse to withstand normal motor startup inrush currents without nuisance opening, while still providing fast response to sustained overloads and short-circuit conditions. This fuse is installed by licensed electricians in industrial, commercial, and residential electrical distribution systems where motor branch-circuit protection is required.

The KLNR125 is suited for motor branch-circuit and feeder protection applications. It fits standard Class RK1 rejection-style fuse holders and fuse blocks, preventing the inadvertent installation of a lower-rated class fuse. Typical applications include motor control centers, disconnect switches, and panel boards where reliable overcurrent protection is critical. The 250-volt rating makes it appropriate for single-phase and three-phase systems operating at 240 volts or below.

Key Features

• 125-amp continuous current rating for motor and feeder branch-circuit protection
• 250-volt AC maximum voltage rating
• Class RK1 rejection configuration prevents substitution with lower-rated fuse classes
• Time-delay design tolerates motor inrush current while protecting against sustained overcurrent
• High current-limiting performance reduces arc flash incident energy and equipment damage

Compatibility

Designed as an OEM-style replacement for Class RK1 fuse holders and rejection-style fuse blocks rated for 250 volts and 125 amps or greater.

Installation Notes

Installation must be performed by a qualified electrician in accordance with the National Electrical Code (NEC). De-energize and lock out the circuit using proper lockout/tagout procedures before removing or installing the fuse. Verify the fuse holder or fuse block is rated for Class RK1 fuses and confirm the circuit voltage and amperage do not exceed the fuse ratings. Do not install this fuse in a holder designed for Class RK5 or non-rejection fuse types.

Technical Specifications

• Amperage: 125 amps
• Voltage: 250 volts
• Fuse Class: RK1
• Response Type: Time-Delay
• UPC: 07945828084

Standard Information

• Brand: LITTELFUSE
• Manufacturer Part Number: KLNR125