Class RK5 Fuse Manufacturer

With excellent reliability and breaking capacity, #HCNR series Class RK5 fuses can be used in circuits withstanding temporary motor overloads and surge currents. The dual-element design ensures high-performance short-circuit and overload protection.

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Class RK5 Fuse

As a prominent electrical components manufacturer, HIITIO specializes in high-voltage DC applications. We hold prestigious certifications, including ISO9001, ISO14001, ISO45001, and IATF16949, attesting to our commitment to quality, environmental responsibility, occupational health and safety, and automotive industry standards. There are four series of fuses designed to ensure the safety of power systems.

The Class RK5 fuse, is a current-limiting time-delay fuse with an interrupting current rating of at least 200,000 amps, designed to protect circuits from overload and short circuits. The rated current is usually 1- 60amps, voltage up to 250VAC and 150VDC, it also known as dual-element fuses, these time-delay fuses withstand current overload for a short time so they won’t open when exposed to harmless temporary surges. 

Top Brand CLASS RK5 Fuse Specification Comparison

Brand Bussmann Edison HIITIO Liitelfuse Mersen
Rated Voltage 250Vac/125Vdc 250Vac/125Vdc 250Vac/150Vdc 250Vac/125Vdc 250VAC;
250VDC (0.1-2.8A; 35-400A);
160VDC (3-30A; 450-600A)
Rated Current 1⁄10-60A 1-60A 10-60A 1⁄10-600A 1⁄10-600A
Breaking Capacity 200kA Vac RMS Sym.
20kA Vdc
200kA RMS Sym. 200kA Vac RMS Sym.
50kA Vdc
200kA Vac RMS Sym.;300 kA Vac RMS Sym.(Littelfuse self-certified)
20kA Vdc
200kA I.R. AC
1/10-60A: 20kA I.R. DC
70-600A: 100kA I.R. DC
Size (Up to 30A) 50.8mm*14.22mm 50.8mm*14.22mm 50.8mm*14.3mm 50.8mm*14.3mm 51mm*14mm
Size (35 to 60A) 76.2mm*20.57mm 76.2mm*20.57mm 76.2mm*20.7mm 76.2mm*20.7mm 76mm*21mm

Features of Class RK5 Fuse

Equipped with UL Authoritative Certification

HIITIO class RK5 fuse has been successfully issued UL JDDZ certification, which is a significant achievement. It’s noteworthy that HIITIO stands out as the sole manufacturer in China at present to be certified by UL, reinforcing our commitment to quality and safety.

High Breaking Capacity Performance

HIITIO class RK5 fuse breaking capacity is up to 200kA, during normal operation, it can withstand high current and maintain the normal operation of the circuit. The overload element provides protection against low level over-current of overloads and will hold an overload which is five times greater than the amp rating of the fuse for a minimum of ten seconds.


It provides equally excellent overload protection for motors and low peak current fuses for other types of loads and circuits, addressing temporary surges such as those caused by currents from transformers and inductors. (In this circuit, current-limiting fuses are only capable of offering short-circuit protection.)


  1. Interrupting all available over-currents within its interrupt rating.
  2. Within its current-limiting capacity, confines the clearance time at the rated voltage to a duration equal to or less than the first major or symmetrical current loop duration.
  3. Restrains the peak let-through current to a magnitude lower than the accessible peak current.


Competitive Price

  • Optimized supply chain, establishing close ties with reliable suppliers
  • Plan procurement, managing inventory
  • Optimized supplier delivery structures

Production capacity

  • 4 semi-automatic production lines and 1 fully automated production line to further enhance productivity and quality control

Quality Control

Comprehensive Certifications

  • UL, cUL, CSA, CE, CB, TUV, SEMKO, CCC, VDE, and more.
  • Actively researching customer needs and industry trends, seeking additional certifications.

R&D Capability

  • Independent laboratory for electrical life testing, breaking capacity testing, high and low temperature testing, etc. 
  • 30+ people R&D team with 10+ years developing experience


  • Pre-sales Services: product consultation, technical support, customized solutions, sample service, and fast delivery.
  • After-sales Services: Respond to your questions and complaints in a timely manner and provide the best solution.

All you should know about RK5 Fuse

What Are the Specific Classifications of Industrial Fuses

According to UL248 and CSA C22.2 No. 248, industrial fuses can be divided into the following categories:

Fuse Type Voltage Rating (AC) Max. Current Rating Classification Time-Delay Requirements UL Standard
Class C 600VAC
DC Optional
1200A Non-renewable
Undefined UL248-2
Class CC 600VAC
DC Optional
30A Non-renewable
Current limiting
12s@2X UL248-4
Class G 480/600VAC
DC Optional
-Current limiting
12s@2X UL248-5
Class H
DC Optional
600A Current limiting
Time Delay
10s@5X UL248-6
Class H
Current limiting
Fast Aciting
Class J 600VAC
DC Optional
600A Non-renewable
-Current limiting
-Fast acting
10s@5X UL248-8
Class K 250/600VAC
DC Optional
600A Current limiting
-Fast acting
10s@5X UL248-9
Class L 600VAC
DC Optional
601A-6000A Current limiting
Bolt-in Time-delay
Undefined UL248-10
Class RK1 250/600VAC
DC Optional
600A Current limiting
Time Delay
10s@5X UL248-12
Class RK5 250/600VAC
DC Optional
600A Current limiting
Time Delay
Class T 300/600VAC
DC Optional
1200A Very Current Limiting
10s@5X UL248-15

What is a Dual-element Design?

The “dual-element” design is a special design for RK5 Fuses aimed at providing better overload protection. Dual-element fuses typically contain two fuse elements: a time-delay element and an instantaneous action element:

Time-delay Element: 

Also known as a thermal element, it is used to handle short-duration over-currents. It has a certain time delay, allowing transient overloads in the circuit to pass through to prevent unnecessary tripping, which is crucial for handling momentary load fluctuations.

Instantaneous Action Element:

Also known as a magnetic element, it is used to handle larger over- This element can respond quickly and rapidly disconnect the circuit to prevent damage from significant overloads.

By combining both the time-delay and instantaneous action elements, dual-element fuses can handle instantaneous overloads in a short time while retaining a certain time delay to accommodate specific transient overload situations.

This makes RK5 fuses more suitable for certain circuits and equipment, providing comprehensive over-current protection.

What Are the Characteristics of Over-Current Protection of High-Performance Current-Limiting Fuses?

High-performance current-limiting fuses provide reliable protection against over-current effects, featuring the following characteristics:

  • High Breaking Capacity:The breaking current capacity reaches 10~200kA, with some products exceeding 500kA.
  • Can limit the short-circuit energy and peak current through the fuse branch to extremely low levels.
  • Fast Short-Circuit Breaking Speed (in milliseconds, potentially below 1ms):
  • High Reliability, Long Life, High Stability: The over-current protection capability remains unchanged for decades without the need for adjustment.
  • Compact Size, Low Cost
  • Convenient replacement of current specifications, current expansion or reduction. The same size series can have many current specifications.
  • Due to low requirements for operating conditions and good adaptability, fuses can be easily coordinated with other electrical components. Through the standardization of characteristic parameters, fuses are easy to use in conjunction with other devices.

What’s the Difference Between RK5 Fuse, And Regular Fuse?

Unlike ordinary fuses, RK5 grade fuses use high melting point alloy materials that quickly melt and open the circuit when high temperature is detected. These materials also have low short-circuit resistance, which allows them to quickly cut off short-circuit current and protect circuits from damage.

In addition, RK5 fuses can quickly cut off the circuit with high breaking capacity. They are usually used in some circuits that require short-term over-current protection, such as over-current when starting a motor. Regular fuses may have lower breaking capabilities and have a wider range of applications including protection of a variety of loads and electrical equipment.

What Should I Pay Attention to When Using RK5 Fuse?

Class RK5 fuses have a time delay function, so they should not be used in circuits where the fuse will be energized for a long time, as this may exceed the fuse’s blowing time and may affect the safety and reliability of the circuit.

Applications of RK5 Fuse

Motor protection

Motor protection

RK5 fuse can be used to protect the motor, especially when the motor is started, transient over-current may occur. RK5 fuse can quickly cut off the circuit to prevent damage to the motor. The time delay feature safely handles harmless starting and inrush currents associated with the motor.

UPS power

UPS (uninterruptible power supply) system

In a UPS system, transient over-current conditions may occur, such as when starting the UPS or when the grid voltage fluctuates. The RK5 fuse is a fast-breaking protection device, suitable for quickly cutting off over-current in the circuit, and can help prevent these over-currents from causing damage to the UPS system.

motor controls solutions

Branch Circuit Protection

RK5 fuses can be employed in branch circuits to protect downstream components and equipment, providing protection against over-current, ensuring that power supply equipment and connected equipment are well protected from over-currents. This includes protection for lighting circuits, power outlets, and other branch circuits in residential, commercial, and industrial settings. 


Yes, we have customers in the United States and Europe. For more information, please contact us.

Yes, we have a distributor policy. Warmly welcome you to discuss with us.

Sure, we can provide free samples after evaluation.

When there is inventory, the delivery time is within a week If there is no inventory, the delivery time is subject to order and will be as early as possible.

Yes, OEM and ODM are available.

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