• Home
  • Courses
  • Machines
    • Transformer
    • AC Motors
      • Induction Motor
      • Synchronous Motor
    • DC Motor
    • DC Generator
  • Power System
    • Circuit Breaker
    • Switchgear
    • Substation
    • Control System
    • Measurement
  • Electronics
  • Blog
  • Contact
    • Contact Us
    • Privacy Policy
Have any question?
[email protected]
Login
StudyElectrical.Com
  • Home
  • Courses
  • Machines
    • Transformer
    • AC Motors
      • Induction Motor
      • Synchronous Motor
    • DC Motor
    • DC Generator
  • Power System
    • Circuit Breaker
    • Switchgear
    • Substation
    • Control System
    • Measurement
  • Electronics
  • Blog
  • Contact
    • Contact Us
    • Privacy Policy

    Basic Electrical

    What is an Electrical Fuse? Types, Properties, and Application

    • Categories Basic Electrical, Circuit Breaker, Electronics
    electrical fuse

    An Electrical Fuse is a vital component of any equipment. It is used as an indicator of a defect in the system. It protects the equipment from overcurrent or overloading.

    Its essential component is a metal wire or strip (fuse wire) that melts when too much current flows through it.

    54 549082 electrical symbol for diode kit kat fuse symbol
    Fuse Symbols

    Just like a fuse, a circuit breaker is another protective switchgear device that operates to provide overcurrent protection of an electrical circuit.

    Table of Contents

    • Working of an Electrical Fuse?
    • Specification of Electrical Fuse
    • Properties & Applications
    • Types of Fuses
      • Round Type (Cut Out) Fuse
      • Kit-Kat type Fuse Unit
      • Cartridge Type fuse unit
      • HRC Tube Fuse Unit
    • Conclusion
      • Related Articles

    Working of an Electrical Fuse?

    Fuses work on the principle of heating effect of current. It consists of a piece of wire called fuse wire made of a metal or an alloy of low melting point. As the current increases beyond a limit, the wire in the electric fuse melts and breaks off. The fuse is then said to have blown off.

    Let’s assume a real-life example. We all connect different types of machines to an electric circuit. Sometimes current drawn by a machine or appliance connected in that circuit gets exceeded from the rated (predetermined) value. This happens due to any one of the following reasons.

    1. Increase in load condition (Overload)
    2. Short circuit
    3. Leakage from the mains

    The damages due to this overcurrent can be limited by a short length of wire known as an electrical fuse.

    An electrical fuse automatically melts due to this excessive current, and thus the circuit is broken. This is how the wiring or any appliance is protected. Otherwise, the wiring and the appliance will be damaged due to the excessive flow of the current in the circuit.

    Shortly, it can be stated that the fuse is a device used to prevent overheating due to excessive current. This in turn protects the insulation of the wire, machine, or appliances from overheating and damage.

    Specification of Electrical Fuse

    Following points should be noted before installing an electrical fuse in an electric circuit.

    1. The fuse is to be put in the live wire (+ve phase) in the mainboard and at the sub-branches.
    2. The size of the fuse wire should be based on the value of current and not on the melting current value.
    3. If the fuse of proper rating is not provided in the circuit and any fault develops due to overload or short circuit, the flow of heavy current will heat up the wires and fire may take place.

    Rated Current of Fuse:

    By rated current, we mean the current that can be carried safely for an indefinite period without undue heating and melting the fuse wire. This rated value also depends upon types of the fuse holder, temperature, and fuse contacts.

    Fusing Current of Fuse:

    It means the value of current at which the fusing wire melts when current passes through it even for a fraction of second. The rated current is approximately half of the fusing current.

    Fusing factor = Minimum fusing current / Rated current of the fusing element

    fusing factor
    Fusing factor

    Properties & Applications

    An Electrical Fuse unit should have following properties:

    1. Easy isolation or separation from terminals.
    2. Box/case, which holds the fuse wire, should be an insulating material such as porcelain.
    3. Ease of replacement.

    The fuse basically consists of a current-carrying element (fusing wire), which melts when heated to temperatures above 170 F. The melting action opens the circuit thereby removing the source of voltage from the circuit.

    fuse
    Fuse wire before and after melting

    The fuse will heat and remain intact provided the applied current does not produce heat that exceeds the melting point of the metal.

    melted fuse
    Melted Electrical Fuse

    It is therefore important that the material used as a fusing element is engineered to accurate thickness, lengths, and widths to carry specific voltage and current loads.

    Obviously, the basic laws of electricity are applied for the selection of fuse ratings for a specific circuit taking into consideration the current required to maintain the normal circuit operation, total energy dissipation, and voltage requirements.

    Selection / Replacing an Electrical Fuse

    A short circuit in the equipment will melt a circuit fuse instantaneously. When a fuse needs to be replaced the exact replacement of a fuse with both proper voltage and current ratings must be used.

    Guide on Fuse Replacement
    Guide on Fuse Replacement.

    The blown-up fuse can indicate the type of service problem in non-functional electronic equipment. Usually, if the glass case of the fuse appears clear and there are broken pieces of the center conductor, the problem has been caused by a slow, gradual overload on the power supply.

    If the glass cover of the fuse is discolored and the center conductor is almost missing, it shows that the fault was caused due to a short circuit. It also indicates that there may be other problems that produced a lot of currents to flow very quickly and destroying the fuse violently with the production of a lot of heat.

    Fuse is a vital component of equipment. It is used as an indicator of a defect in the system. It protects the equipment from the overcurrent/ overloading.

    An Electrical Fuse unit should have the following features:

    1. Easy isolation or separation from terminals.
    2. Box/case which holds the fuse wire should be made of an insulating material such as porcelain.
    3. Ease of replacement.

    Types of Fuses

    There are different types of fuses available in the market. We select them based on our application. Some of the important types of electrical fuses are listed below.

    Different Types of Fuses
    Some of the Electrical Fuses
    1. Round type fuse unit (cut out) (Rewirable)
    2. Kit-kat type fuse unit (Rewirable)
    3. Cartridge type fuse unit.
    4. HRC type Fuses
    5. Automatic Cut Out
    6. Plug type
    7. Expulsion fuse
    8. Liquid fuse
    9. Drop out fuse.
    10. Mini Circuit Breaker

    The first four in this list are discussed in the below section.

    Round Type (Cut Out) Fuse

    Round Type (cut out) fuse looks similar to a ceiling rose. It is made up of Bakelite or porcelain material. Its base is fixed on a wooden board with a screw. This type of fuse is not used as a common fuse.

    Round Type Cut Out Fuse
    Round Type (Cut Out) Fuse

    There are two terminals on the base in which the fuse element is fitted. Threads are provided on the box as well as on the cover for placing and replacing purposes.

    Small holes are provided on the cover, for air entrance. The holes also provide a passage for gases formed due to melting (burning) of the fuse element.

    Following are disadvantages of this type of fuse.

    • One of the terminals is always energized with live (+ve) wire of the supply.
    • Due to the above reason, it is difficult to replace the fuse element with mains on. The main switch must be open.
    • When the fuse blows off there is too much arcing and the unit may be damaged.

    Kit-Kat type Fuse Unit

    Kit-Kat type is a semi-closed type electrical fuse unit. Neither it is kept in free air nor it is completely enclosed.

    These are used for household or laboratory purposes mostly. This type of fuse unit can be rewired; even the cut out terminals are energized without taking any safety precautions.

    Kit kat fuse
    Kit-kat fuse

    This can be fitted on wooden blocks or boards or also used in iron-boxes. (In Iron-clad switch.)

    Following terms are used in connections with this type of fuse units.

    • Fuse links: This part consists of a fuse element.
    • Fuse carrier: This carries a fuse link.
    • Fuse base: It is a fixed part carrying fixed contact terminals.

    Fuse base carriers are made of porcelain, whereas contacts and terminals are of hard bronze materials.

    Fuse carrier on which the fuse link is kept can be taken out very easily and safely (even with the switch in ON position). Fix contacts are fitted to the base.

    Both terminals and wires are fitted to the top terminal. No fuse element is kept in the neutral wire. For this purpose, Neutral Link (copper or bronze) is provided in D.P.I.C. switches.

    Double Pole Iron Clad Switch
    DPIC Switch

    When fuse bridge with fuse element is inserted and the switch is made ‘on’ then only the circuit is completed. These fuse units are rated as 5.15, 30 up to 300 Amps.

    These types of fuse units are very simple in operation and very cheap and easy for replacement.

    Cartridge Type fuse unit

    Cartridge types of fuse units are completely enclosed.

    The fuse element is kept in a peculiar shape just like a bucket known as the cartridge. This container is filled with the materials ’quartz’.

    what is fuse
    Cartridge Fuse

    The container is heat resistant; good insulating material and it is sealed completely. If the fuse goes off the complete unit is to be replaced. Therefore it is costly.

    It cannot be rewired (in some types, rewiring is possible).

    There is an index circle on the container, which under normal condition is clear, but when the fuse blows off it becomes dark. These fuses are fixed in fuse carriers just like a kit-kat fuse in the D.P.I.C. unit.

    HRC Tube Fuse Unit

    HRC fuse unit means a high rupturing capacity fuse unit. These are similar in construction to cartridge types with the exception that the fuse wire can carry heavy current for a known short time period.

    HRC Fuse
    HRC Fuse

    This heavy current can be much more than the normal rated current. During this time if the fault is removed, its use does not blow off otherwise it blows off and breaks the continuity of the circuit. Thus these fuses are sometimes also called Slow Blow Fuses.

    The cartridge of HRC type is either made of glass or some other chemical compound and has airtight construction to avoid the effect of atmospheric air on the fuse material (results in lowering its rated capacity due to continuous slow oxidization of the wire material).

    These fuses are available in 2A to 800 Amps. Capacity ranges. The fuse element used here is silver. The most popularly used fuses in electronic circuits are 2 amp to 5 amp.

    Conclusion

    The fuse basically consists of a current-carrying element, which melts when heated to temperatures above 170°F. The melting action opens the circuit thereby removing the source of voltage from the circuit.

    The fuse normally heats up and remains intact provided the applied current does not produce heat that exceeds the melting point of the fuse metal wire. It is therefore important, that the material used as a fusing element is engineered to accurate thickness, lengths and widths to carry specific voltage and current loads.

    For this the basic laws of electricity are applied for selection of fuse ratings for a specific circuit, taking into consideration the current required to maintain the normal circuit operation, total energy dissipation and voltage requirements.

    A short circuit in the equipment will melt the circuit fuse instantaneously. When a fuse needs to be replaced the exact replacement of a fuse with respect to both proper voltage and current ratings must be used.

    The blown up fuse can indicate the type of service problem in non-functional electronic equipment. Usually if the glass case of the fuse appears clear and there are broken pieces of the center conductor, the problem has been caused by a slow, gradual overload on the power supply.

    If the glass cover of the fuse is discolored and the center conductor is almost missing, it shows that the fault was caused due to a short circuit or other problem that produced a lot of currents to flow very quickly and destroying the fuse violently with the production of lot of heat.

    Fuse is a vital component of any equipment. It is used as an indicator of a defect in the system. It protects the equipment from over current or overloading.

    Related Articles

    • Types of analog instruments
      Three Types of Analog Instruments

      An analog instrument is one in which the output or display is a continuous function…

    • Stepper motor types
      Types of Stepper Motor

      A stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements. …

    • Tulip contacts of Vacuum Circuit Breaker
      Basic Types of Switchgear Components

      Before learning about different switchgear components, let us understand what is switchgear. The apparatus used…

    • what is fuse
      What is a FUSE and How it Works?

      A fuse protects an electrical circuit or device from excessive current when a metal element…

    • 4 2Bmajor 2Btypes 2Bof 2Bsubstations
      4 Major Types of Electrical Substations

        The assembly of the apparatus used to change some characteristic (e.g. voltage, a.c. to…

    • types of electrical relays
      Types of Electrical Relays

      We have already discussed the working of electrical relays. Now we are going through different…

    • Share:
    Tesla Edison
    Tesla Edison

    Tesla is an Electrical Engineer, Physicist and an Inventor in making. He is a good writer and author of many courses and articles published in this site.

    Previous post

    Introduction to PCB Assembly Process
    June 12, 2020

    Next post

    Electrolytic Capacitor - Types, Construction, Polarity and Leakage Current
    July 17, 2020

    You may also like

    dc bias characteristics of capacitor
    What is a capacitor’s DC bias characteristic?
    22 March, 2023
    passive components
    Understanding Passive Components in Electrical Engineering
    3 March, 2023
    used oscilloscope buying guide (1)
    Buying a Used Oscilloscope: A Guide to Help You Decide
    28 February, 2023

      2 Comments

    1. Nigel
      July 27, 2020
      Reply

      Thank you so much for sharing! This is Interesting and amazing article!

    2. Abhay
      December 23, 2022
      Reply

      Thank you so much sir thank you very much for covering all types of fuse.

    Leave A Reply Cancel reply

    Your email address will not be published. Required fields are marked *

    Search Here

    From Blog

    Types of Power plants
    Types of Power Plants
    28Jul2015
    SF6 Circuit Breaker
    Methods of Arc Extinction in Circuit Breaker
    23May2014
    plc 2
    Introduction to PLC Ladder Programming
    02Aug2017
    core-type-transformer
    Core Type and Shell Type Transformers
    13Nov2017

    Categories

    • Alternator
    • Arduino
    • Basic Electrical
    • Battery
    • Books
    • Cables
    • Capacitor
    • Career
    • Circuit Breaker
    • Control System
    • DC Generator
    • DC Generator MCQ
    • DC Generator Solved Problems
    • DC Motor
    • DC Motor MCQ
    • Drives
    • Electric Vehicles
    • Electrical Circuits
    • Electrical Machines
    • Electrical Relays
    • Electrical Safety
    • Electronics
    • Embedded System
    • Exams
    • Generation
    • Guest Post
    • HVDC
    • Instrumentation
    • Interview Questions
    • Locomotives
    • MCQ
    • Measurement
    • Microcontroller
    • Objective Questions
    • PCB
    • PLC
    • Power System
    • Problems and Solution
    • Projects
    • Resistor
    • Signals and Systems
    • Single Phase Motors
    • Substation
    • Switchgear
    • Synchronous Motor
    • Three Phase Induction Motor
    • Transformer
    • Transmission Line
    • Uncategorized

    Copyright © 2021 Study Electrical, Inc.

    © StudyElectrical.Com 2021

    Login with your site account

    Lost your password?