What is Fuse: Definition and 48 Discussions

In electronics and electrical engineering, a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby stopping or interrupting the current. It is a sacrificial device; once a fuse has operated it is an open circuit, and must be replaced or rewired, depending on its type.
Fuses have been used as essential safety devices from the early days of electrical engineering. Today there are thousands of different fuse designs which have specific current and voltage ratings, breaking capacity, and response times, depending on the application. The time and current operating characteristics of fuses are chosen to provide adequate protection without needless interruption. Wiring regulations usually define a maximum fuse current rating for particular circuits. Short circuits, overloading, mismatched loads, or device failure are the prime or some of the reasons for fuse operation. When a damaged live wire makes contact with a metal case that is connected to ground, a short circuit will form and the fuse will blow.
A fuse is an automatic means of removing power from a faulty system; often abbreviated to ADS (Automatic Disconnection of Supply). Circuit breakers can be used as an alternative to fuses, but have significantly different characteristics.

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  1. J3J33J333

    I Can you put out a fuse (fire) with a laser?

    I was wondering you if you could use a laser to put out a fuse or to stop combustion? Could you use some form of laser/laser cooling to put out an explosion mid-explosion?
  2. JCMacaw

    Meaning of fuse current rating for fuse holder

    Does anybody know what the 1/10 meaning is in the current rating description for a fuse holder? 1/10-30A 600V For No. of Fuses For Fuse Current, A Voltage Wire Connection Type For DIN Rail Size, mm Features 1 1/10-30 600V DC/600V AC Screw Terminals 35 Covered Terminals...
  3. D

    MicroVoltage fuse (Now "Sensing the Flame-Front of a Plasma")

    I have not had any luck finding a fuse that will burn out fast at voltages below a volt. Is there no such thing? Thanks!
  4. R

    Wires in an circuit, different materials, heat

    Homework Statement In an electric circuit, consisting of copper wires with cross section area of Sc=5mm2 and a temperature of t=25C, a lead fuse is added melting when the copper wire temperature increases by Δt=25C. Find the cross section area of the lead fuse wire Sl=x. specific heat...
  5. Richie Smash

    What is the Suitable Fuse Rating for the Mains Supply in Question 35?

    Homework Statement Hello, the question is number 35 in this picture here: http://uploads.im/uEWAf.jpg It states, ''A suitable fuse rating for the mains supply has current rating - (A)10A (B)15A (C)30A (D)60AHomework Equations V = IR P = IV P = I^2 R P = V^2/R The Attempt at a Solution I...
  6. PJP

    Which fuse should i use for a step down transformer

    hello every one! I'm working on a project to vibrate an iron string with an electromagnet. I've a 230 v step down transformer with "12-0-12 1 amp" output and a 230 v "12-0-12 5 amp" output. I'm confused with which FUSE should i go with. i have a 3 amp and a 5 amp fuse. also I'm planning to use...
  7. G

    How to get the fuse rating you need for a DC power supply

    building a DC supply with a load voltage of 3.3V and load current of 3.3mA. all the books and schematics I'm seeing is that they're putting the fuse in the primary of the transformer, why? if i were to fuse the primary as well how do i get the rating of the fuse that i'll need? its said in my...
  8. H

    Automotive Voltage check on car electrical components

    Hi I watched this video of a guy testing a fusebox with a multimeter: if you skip to 6:10 he uses a multimeter on a particular fuse and when putting the black lead on good ground of car and red lead on either side of the fuse he gets the same reading on both sides. He even comments that there...
  9. G

    Fuse blown but there's still voltage measured

    Hi, i have a question regarding why voltage can be measured even after a fuse blown. The application i have gives an synchro output L1, L2 and L3 with reference voltage as Reference High(RH) and Reference Low(RL) of 115Vac. The receiving end failed to receive any signal and one of my fuse across...
  10. berkeman

    Have you seen this in-plug fuse arrangement before?

    I bought a small floor fan yesterday, and in reading the instructions (yes, some of us do read the instructions), I was surprised to see this. Have any of you seen a fuse in the AC mains power plug like this before? If I hadn't read the instructions, it would have never occurred to me to look...
  11. F

    Install Fuse: Positive or Negative?

    hello, I am trying to wire up an LED light bar on my car, but I'm having trouble understanding why the fuse and on/off switch "MUST" go on the positive terminal. To start off a fuse is technically is a switch protecting our loads and will open the circuit (burn) when there is an overload...
  12. Aizen

    B What is the heaviest element that a star will fuse?

    Is Iron the heaviest element a star will fuse through nuclear fusion or will it continue to Iron into a heavier element.
  13. A

    Is it possible to fuse more than two atoms at once?

    I'm writing a paper for my teacher, not an assignment, just because I was interested in the topic. I've searched a lot of websites, but most only talk about fusing two atoms, and not saying if it is possible to fuse more than two at the same time.
  14. davenn

    Fuse Replacement Guide: An Oldie But a Goodie

    an oldie but a goodie ... has seen a few variations over the years :wink:
  15. N

    Can a low voltage situation cause a fuse to blow?

    Hello all. First, let me say that have very little education in the electronics field, but I do know the basics. I recently got hired as a service tech for pressure washers and had encountered a unit that had a small engine (electric start 12v) with a blown fuse. A co-worker of mine has been...
  16. S

    Why Is the Answer to the Fuse Question B?

    I don't get it at all.
  17. Evanish

    Can an Alpha Particle Fuse with a Hydrogen Atom?

    I was wondering if alpha particles created by radioactive decay ever have enough energy to fuse with something else (e.g. hydrogen or another alpha particle).
  18. J

    Engineering Calculating fuse size, current and voltage in a circuit

    (a) Calculate the size of Conductor and Fuse, the amount of Current through the conductor, Voltage ACROSS the existing LOAD and power consumed by the EXISTING LOAD under normal circuit condition (when the switch of the above circuit will be closed). (b) Calculate the overload current...
  19. T

    Clarification of Onderdonk's Fuse Equation Assumptions

    Hi all, I am trying to get an understanding of Onderdonk's Fuse Equation: ##I_{fuse}=Area*\frac{\sqrt{log\left(\frac{T_{melt-T_{ambient}}}{234-T_{ambient}}+1\right)}}{33*Time}## Empirically I do not see that this function accurately depicts the behavior of the wires I am using. For example, I...
  20. thankz

    Are Car Audio Amplifier Fuse Ratings Misleading?

    I just bought a few car audio amplifiers, they are advertised as 6000 watts and 800 watts respectively but the fuse ratings are 60ampsx2 and 20ampsx2 so am I missing something here? I purposely bought higher wattage amps because I believe their only advertising peak power (assuming they use...
  21. rotflqtms

    Adding 3 new wires to 1 fuse in fuse box in car

    I wanted to install a few cigarette lighters in my old 1996 Toyota Camry that my sister just gave me since it only comes with one, and I want to have a dash cam/parking cam AND to charge my phone, and while I'm at it, add one in the back. I located the fuse box, and will find an accessory fuse...
  22. K

    Two cars collide and fuse together

    Homework Statement Car= 25m/s on x-axis and truck= 20m/s on y-axis Car is 1250 kg truck is 1900kg They collide and fuse together and the combined wreckage slides of the road. With final velocity Vf and at angle ° with respect to x-axis . there are no external forces acting for The...
  23. Tesladude

    Easy Q about fuse placement in transormer-based power supply

    Making an amp for a friend, useing a split supply with center tabbed transformer as ground for the chip, I think I heard the current alternates comeing from = and negative into ground, or from = and ground into negative or somthing, so where do I put the fuse?
  24. C

    How to Pick the Right Fuse for Your Needs

    Hi Guys, I was finish with my load calculation, and now my problem is what fuse to use. As i surf the net there are lots of Fuse to be found in the market. Although my calculation is base only in theoretical basis, so my question is when to use this following fuse. 1.) Controlled vented...
  25. I

    When Atoms Collide: Exploring the Fusion Process and Its Effects"

    Hello, i'd just like to know do atoms fuse together the instant that they make contact after overcomming repulsion or does it take time? I've been led to believe that when we touch something we never actually touch it since electrons repel each other and we can't generate enough force to...
  26. O

    Finding the Right Fuse for 24V DC Motor Application

    I have an application where I am using a 24V DC motor to drive a ball screw. If someone isn't paying attention and they hit the mechanical stop on the ball screw, the current is going to spike to about 200 Amps. The normal running current is about 35 amps, and the max current is 60 amps...
  27. J

    Amount of Energy to Fuse Two Atoms

    I was wondering if there was a simplified equation to determine the amount of energy required to fuse two atoms together (for example a sodium atom with a hydrogen atom to form a magnesium atom).
  28. B

    Finding Distance Using a Fuse, Current & Magnetic Field

    Hello. I want to help a friend solve a problem. I'm having trouble finding the right way to solve for distance for this problem. I am given 2 parallel wires connected by another wire or perhaps a conducting fuse. His information is kind of vague, sorry. The current goes up one of the wires...
  29. S

    Will a 5A Fuse Melt with 20 Bulbs in Parallel?

    If I have a fuse with a rating if 5A and when I connect 10 bulbs in parallel, the current flowing will be 5A. When this happens will the fuse melt? Or does the current have to be more than 5A for it to melt?
  30. J

    Circuit problem: Will the fuse blow out?

    Homework Statement Number 14. Homework Equations A fuse will blow out if there the current going through it is larger than the ratings of the fuses. V = IR The Attempt at a Solution The current from the battery comes out of the negative side (small line) and goes through F1...
  31. P

    What is the Young's Modulus and tensile strength of fuse wire?

    Information for/properties of fuse wire Homework Statement Recently in physics class we were doing a practical activity, in which we were asked to obtain the value of Young's Modulus for certain materials. One of the materials we tested was fuse wire. Here's where the problem comes in...
  32. T

    Fuse Tap Circuit Problem (easy?)

    Hello. I am a programmer and haven't done anything with hardware since my physics class a few years ago. Needless to say I've forgotten a few things and after a few hours of searching google and troubleshooting I'm unable to fix my problem. I am using a fuse tap (it allows me to use a fuse as...
  33. L

    Can a 60W 120V Appliance Surpass the Max Household Current and Blow a Fuse?

    If an appliance is rated 60W 120V, R=1 ohm. Then I = V/R= 120/1 = 120A. But the household current is 13 A (max). Will the fuse blow?
  34. A

    Fuse Breaking Current: Explained

    Dear all , i have an important question which i need answer for it , if you look at a catalog for fuses you will find the fuse rated current which for example is 10 A and you will find a value called minimum breaking current and it is usually higher than the rated current for our example...
  35. S

    Why don't solids fuse spontaneously?

    Suppose I have single crystal of Quartz, and I break it in half. It took energy to break the crystalline bonds of the crystal. Now, I take my 2 crystals, and fit them together along the break line, so that they are flush with each other. Why should the 2 crystals not spontaneously conjoin...
  36. T

    What equpment can be used to time a quick blow fuse

    What equpment can be used to time a "quick blow" fuse Hi everyone, I just received a planning and design lab that requries me to measure the time taken to for a "quick blow" fuse to blow when the current in the equipment it is in, rises above the predetermined point. The times being dealt...
  37. T

    Fuse current of silicon nanowire

    Hello, I'm studying for a project a rectangular-cross sectionned suspended silicon nanowire. My question is very simple: at which current will my nanowire break? The melting point is 1687K and I start at 300K I don't really know where to start since the resistance, the thermal...
  38. mheslep

    T Pyxidis Supernova: Energy Release Compared to SN1054

    I see from this http://www.thesun.co.uk/sol/homepage/news/2795981/Supernova-may-wipe-out-the-Earth.html" was day light visible and was 6300 ly away. Assuming the explosions have similar energies, we should receive, what, 4X the energy on Earth from a T Pyxidis explosion? What is the likely...
  39. B

    Fuse Resistors, CFLs, and God Awful SMPSes

    The other day I came into my living room, and noticed that the CFL in one of my lamps was flickering like crazy. Of course having a propensity to possibly fatal curiosity as some humans do, I walk over and grab the base to see if maybe the bulb isn't seated properly. The base of the bulb is...
  40. M

    Why is a fuse connected in the live wire only?

    why is fuse connected in the live wire only? as current is same throughout the circuit( it is produced simultaneously in the whole circuit ie it does not 'originate' from any source) putting the fuse anywhere in series with the circuit should work.
  41. P

    Why does fuse wire always break in the middle?

    Hello, I have been looking this thing up for a couple hours now on google and textbooks. So far, I got nothing... When you use a fuse wire in a circuit, why does the fuse wire always melt in the middle? I don't see how the middle of the fuse wire gets hotter than the ends unless the middle of...
  42. A

    Understanding Causes of Hall Light Blowing Fuse

    Hi, can anyone explain this: last night i switched on the hall light and the light blew. but it also blew the 5A fuse back at the dis board. My question is, why ? Ive heard this happen before but when someone asked why, i couldn't explain it...
  43. V

    Fuse Wire Length and Capacity: A Discussion

    Homework Statement does the length of the fuse wire influence its cpacity? why? Homework Equations R=pL/a The Attempt at a Solution My teacher said no. I think it should because R depends on L Thanks for your time.
  44. T

    Is My Circuit Overloaded and Causing the Fuse to Blow?

    I have a circuit in my house that sometimes blows its fuse. Now, electricity is not my field at all so I'm asking you guys. I know the fuse is 10 amps, I use perhaps 3,5 kW on this circuit, and we have 230 V over here. Don't know if that's enough info to make any form of judgement on whether or...
  45. Greg Bernhardt

    Where is the 1995 Honda Accord Fuse Box Located?

    Anyone know the location of the 1995 Honda Accord interior fuse box?
  46. P

    Fuse Rating Problem: Which is True?

    Some physics books said that the fuse rating is the maximum current that the fuse can carry without melting it. But some said that the fuse rating is indicating the current at which the fuse would immediately melt. Which is true?
  47. M

    Selecting the Right Fuse Size for Compressors

    What do i have to take into consideration when deciding what fuze sizes are needed for the Medical Air Compressor, or generally any compressor. Compressors; cooling units, refrigerators, blowing units (cooling systems). Simply to say any compressor, any kind. Example; a brand new...
  48. S

    Atoms whose protons have been stripped off can fuse?

    A plasma consists of both ions and uncharged particles of gases. Is it possible for the uncharged particles to fuse or only atoms whose protons have been stripped off can fuse?