The diameter of the copper wire for the fuse is 10 amps. How to make an electronic fuse with your own hands
A homemade copper wire fuse can be a great temporary way to replace a blown fuse. But if you decide on this, then it is extremely important to choose the right section of the very conductor that you will use. Why is this important, what are the causes of blown fuses and how to temporarily eliminate this inconvenience, we will consider in our article.
Let's start with the most important - with the causes of blown fuses. After all, nothing happens just like that, and before putting the “bug”, it is necessary to determine the reasons for the failure of the fuse.
There may be several of them:
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The most common and common cause of a blown fuse is a short circuit. As a result of this event, the current increases sharply, to which the fuse in the fuse reacts, blowing out. |
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Also, a fairly common occurrence is the burnout of the conductor when the drive mechanism of the supply circuit is jammed. In this case, the fuse acts as overload protection. |
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next possible cause the fact that you need to look for a wire for a fuse may be a power surge. With a sharp and most importantly long-term decrease in voltage, the current, according to Ohm's law, increases proportionally. This may cause the fuse to blow. With short-term jumps, this happens extremely rarely. |
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Another possible option is the frequent operation of the fuse on the verge of tripping. When the current flowing through it is close to rated, the fuse wire gets very hot. Then it cools down and heats up again. This mode changes the structure of the metal, due to which the fuse can blow at much lower current values. |
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It is to exclude such cases that high-quality fuses are produced from the purest metals. They have a change in structure with frequent temperature changes is minimized. |
Wire diameter selection and fuse repair
Well, now let's move on to the main issue of our article - the choice of diameter and the repair itself. Let's start with the first one.
Selection of conductor diameter
The diameter of the conductor in the fuses is clearly calculated. If you are replacing, you must install a conductor of the same diameter. Otherwise, your fuse will not perform its function of protecting the electrical network.
- This can be done in several ways. The easiest way is to take the wire size for the fuse, and a table of standard values will allow you to make a choice. To do this, just measure the diameter of the wire.
- The diameter of the wire can be measured with a caliper or even a regular ruler. If the fuse wire diameter is too small, measurements can be made as follows. We wind the wire on any small object - a lighter, a pencil, a pen.
- It is advisable to make 10-20 turns, for greater measurement accuracy. We make the turns as dense as possible, to exclude the space between them. Then we measure the diameter of all turns. The resulting value is divided by the number of turns. Here is the wire size for the fuse.
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Ten of them were killed immediately.
220 volts is no joke to you.
How to repair a fuse, how to choose a wire or wire to replace the fuse filament.
Hello!
Repairing a fuse has to be done when it has burned out, and the store is closed or far away, but using an electrical appliance without a fuse, and everyone should know this, is far from safe. I partially touched on the issue of fuses in this one, where the principle and purpose of fuses was considered.
In the best case, the device with the “bug” installed will burn out so that it becomes clear why the fuse failed, in the worst case, this can lead to a fire and other no less safe consequences.
We will mainly touch on low-power fuses. But their principle is the same. A ceramic or glass tube (maybe another modern material) inside which there is a wire or plate, and in powerful fuses of the PN-2 type, the space around the wire can be filled with quartz sand or other arc-quenching material. In low-power fuses, there is usually no filling material.
So, you have blown a fuse (otherwise you would hardly have looked for this material) and you need to “reinvent the wheel”. Look at the photo and you will see that the fuse consists of a glass tube and two metal caps. The pitfall here creeps up imperceptibly - it is not always possible to remove the cap without damaging the tube, since not only does it sit tightly, it also happens to be glued.
How to disassemble a fuse.
Based on the above, there are four options:
Why is it bad when the wire is outside. The higher the voltage used, the more it tends to "run away". Such a path for high voltage maybe even soot, let alone a thin layer of copper, which can spread under the influence high current. That is why it is important to place the conductor in a tube and other protective material. And it is for this reason that it is not recommended to get too carried away with the procedure for restoring the fuse. Over time, a lot of soot and molten metal accumulate in this way and the voltage forms an arc through which current also flows freely.
All other fuses are structurally similar. If you still have a problem and you can’t get to the fuse, write a question in the comments. I visit the site at least once a day, so you will receive a response promptly.
Online fuse calculation.
It remains only to determine what to make the wire from and how to calculate it.
Most often, the wire is made from copper wire(can be tinned, it does not play special significance). But so that the fuse does not become a "bug", you need to choose the correct section of the wire. To do this, you can use both tables:
And the calculations in the form of an online calculator, which I will post a little lower. First, let's talk about calculations. If you still do not know about the long-term permissible current, then you need to get acquainted with this concept, and if you know, then you will be surprised by carefully looking at the table. For example, a wire with a cross section of 2.4 mm² can withstand a current of 300 amperes. It would seem, why then is it protected by a 25 ampere automatic machine? The fact is that at 300 amperes it heats up very much. If there was insulation on it, it would have turned to ash long ago with such a current.
Fuse wire diameter.
How to determine wire diameter. There are three methods for this:
What do you need to know about this formula?
You may notice that a strange multiplier of 1.885 has been added. The fact is that the wire cross section in some strange way does not correspond to the mathematical formula for calculating the area of a circle, and if you do not apply this coefficient, then you will get a completely different result. You can trust me. I didn't just paste this formula from somewhere, I did the calculations (and more than one before I wrote it here). For those who are interested in repeating, you will need a micrometer and a bunch of different wires. Perhaps your coefficient will become more accurate, but within this figure. This coefficient is valid for copper wire, for aluminum it will be 1.309, for other materials it may also be different. ( There are different formulas on the Internet, but as I said, I don’t know where they came from, I did my calculations before giving this formula). Well, how about without the practical part. Let's say we have a 0.5 mm² wire and 15 wires. 0.5 / 15 \u003d 0.033 mm² the cross section of one wire, now we substitute the result into the formula and get 0.282 mm. We look at the table and find that a wire with a diameter of 0.25 can withstand 10 amperes, which means ours will withstand about 12 amperes.
In modern electrical appliances, fuses are found everywhere, or, to put it “scientifically”, fuse-links. They protect the network and the device itself from short circuits or overload. The design of fusible inserts is the most diverse, as are the sizes. Rated currents and voltages for which fuses are produced correspond to standard values. The overall dimensions of the fuse depend on the value of the rated voltage of the fuse, namely the length, the higher the rated voltage of the fuse, the greater the distance between the contacts. The rated current is determined by the cross section of the wire inside the fuse.
Although resettable electrical fuses can already be found in more expensive devices, most devices are still equipped with conventional fuses.
General concepts, familiarity with tubular fuses
The most common fuses are the so-called tubular ones. They are a ceramic or glass tube with metal cup contacts at the ends. These cups are interconnected by a wire, the cross section of which, as already mentioned, determines the rated current of the fuse. This current is indicated on the tube or one of the contact parts of the fuse. For example: F0.5A - this means that this fuse is rated for a current of 0.5 amperes.
On electric circuit diagrams the fuse is indicated by a rectangle with a straight line passing through it. Next to the conditional graphic designation, its reference designation is indicated, for example F1 (F - fuse, fuse in English); and if it does not clutter up the circuit - the rated current, for example 100 mA.
Description of the principle of operation of the fusible link (fuse)
The principle of operation of the fuse is extremely simple. When flowing through the wire connecting the contacts of the fuse, the rated current, this wire is heated to a temperature of about 70 ˚С. But when the current is exceeded, the wire heats up more strongly, and when the melting temperature is exceeded, it melts, i.e. burns out. It is for this reason that fuses are also called fuses or fuses. The higher the current, the faster the heating, the faster the melting occurs, and, accordingly, the fuse blows.
Thus, all fusible links work on the same principle - an excess of current in the circuit causes overheating and melting of the wire inside the fuse and, as a result, disconnecting this circuit from the mains supply.
There are two main reasons for the fuses to burn out: power surges and a malfunction inside the appliance itself.
Fuse check, fuse failure indicator
You can check the fusible link with any "dialing" or tester. The task is to make sure that the fuse circuit is intact and able to conduct electricity.
Checking the fuse, in order to avoid electric shock, is only allowed when the appliance is turned off!
In addition, you can buy or make your own fuse blown indicator, which will notify you when the fuse is blown.
The scheme of such a device is extremely simple and is shown in the following figure.
In parallel to the contacts of the fuse, through the current-limiting resistor R1 and the diode VD1, to protect against reverse voltage, the HL1 LED is connected. Diode VD1 must be selected based on the reverse voltage exceeding the mains. For 220 V network reverse voltage for the diode VD1 there must be at least 300 V, such requirements are met, for example, by the diode 1N4004 or the domestic KD109B.
The indicator does not light if the fuse is good, and lights up if it is blown.
It is very convenient to supplement power supplies of your own manufacture with such a scheme.
By slightly changing (simplifying) the circuit, you can get a blown fuse indicator on a neon lamp, although it does not look as effective as an LED.
Selection of a fuse according to the rated power of the electrical appliance
After checking the fuse and determining that it is out of order, it must be replaced. And for this you need to find out its face value in order to perform the correct replacement.
If you know the power consumed by an electrical appliance, usually it is indicated on the nameplate of the appliance, you can independently calculate the rated current of the fuse using the following formula:
Inom = Pmax / Unom
The rated current (Ampere) is equal to the maximum power (Watts) of the electrical appliance divided by the rated mains voltage (Volts).
For example, the fuse in the TV burned out, it is not possible to make out what is indicated on the fuse case, its value, but the power consumption of 150 VA is indicated on the nameplate of the TV.
150 / 220 = 0.68, rounded up to the nearest higher standard value - 1 A.
Please note that when calculating the fuse current rating, you get an exact current value that may not correspond to a range of fuse ratings. Therefore, the calculated value, taking into account a margin of 5%, is rounded up to the nearest standard value.
For simplicity, you can use a ready-made table that shows the ratings of standard fuses for various consumers based on their connection to a 220 V household network.
Fuse replacement
When replacing a fuse, in order to avoid electric shock, be sure to unplug the appliance from the mains!
There is such an unspoken rule, if after the second replacement the fuse blows again, look for a malfunction in the electrical appliance itself. So the appliance needs to be repaired.
In no case do not install a fuse for a higher current, such attempts will definitely lead to even more damage to the device up to its unrepairability!
Be careful when buying a new fuse. Correctly determine the type and current rating of the replacement candidate. It is better to purchase electronic components from trusted suppliers who guarantee product quality, for example, Conrad Electronic. The full range of fuses can be found at the link - https://conrad.ru/catalog/predohraniteli_s_plavkoy_vstavkoy.
Fuse repair
Typical laymen believe that fuses are beyond repair, in fact, this is not the case. Most types of fuses can be repaired and given a second, third, etc. life. The fuse case, as a rule, is destroyed extremely rarely, the wire inside burns out, and the repair consists in replacing it. The main task in this case is to use a wire similar to the one that was in the fuse.
If you need to replace the fuse very quickly, but there was no spare at hand, then you can use the following method:
Remove the paintwork from the wire (clean it to a shine) and wind several turns on each fuse contact, then insert the fuse into the holder. This method in the common people is called - "bug". With it, you can very quickly check the health of the device, but it is not reliable and can be used as a temporary solution to the problem.
The next method, the so-called "factory". The repair will require a soldering iron, and possibly a dremel or a screwdriver, but the fuse after repair will look like it was fresh from the factory.
Heat the ends of the cup contacts with a soldering iron and free the holes in the ends from the solder using a toothpick or something similar. It happens that the holes are too small or completely absent, then you have to drill them. Use a drill with a small diameter of 1 - 2 mm.
Pass a wire of suitable diameter through the holes and solder it to the cup contacts.
The fuse is ready!
Fuse wire diameter selection
As described above, to repair the fuse, it is necessary to replace the blown wire with a wire similar to the one that was in the fuse before it burned out.
Factory fuses use wires made of various metals: silver, copper, aluminum, tin, lead, nickel, etc. At home, we are unlikely to be able to determine the material of the wire of a blown fuse, and we have ordinary copper wire at hand. But just in case, we give a table of wire diameters, depending on the rated current of the fuse, containing, in addition to copper, aluminum, steel and tin.
| Fuse current, A | 0,25 | 0,5 | 1,0 | 2,0 | 3,0 | 5,0 | 7,0 | 10,0 | |
| Wire diameter, mm | Copper | 0,02 | 0,03 | 0,05 | 0,09 | 0,11 | 0,16 | 0,20 | 0,25 |
| Aluminum | - | - | 0,07 | 0,10 | 0,14 | 0,19 | 0,25 | 0,30 | |
| Iron | - | - | 0,13 | 0,20 | 0,25 | 0,35 | 0,45 | 0,55 | |
| Tin | - | - | 0,18 | 0,28 | 0,38 | 0,53 | 0,66 | 0,85 | |
| Fuse current, A | 15,0 | 20,0 | 25,0 | 30,0 | 35,0 | 40,0 | 45,0 | 50,0 | |
| Wire diameter, mm | Copper | 0,33 | 0,40 | 0,46 | 0,52 | 0,58 | 0,63 | 0,68 | 0,73 |
| Aluminum | 0,40 | 0,48 | 0,56 | 0,64 | 0,70 | 0,77 | 0,83 | 0,89 | |
| Iron | 0,72 | 0,87 | 1,00 | 1,15 | 1,26 | 1,38 | 1,50 | 1,60 | |
| Tin | 1,02 | 1,33 | 1,56 | 1,77 | 1,95 | 2,14 | 2,30 | 2,45 | |
Fuse Wire Diameter Calculation
If you need a fuse for a current not listed in the table above, you can use the formula to calculate the diameter of the copper wire depending on the rated current of the fuse.
For low currents (when using a thin wire with a diameter of 0.02 to 0.2 mm), the formula is as follows:
d = Ipl k + 0.005
For high currents (when using wire with a diameter of more than 0.2 mm), the formula is:
Where Ipl- fusible link current in amperes, to and m coefficients depending on the material of the conductor can be determined from the following table.
Determination of fuse wire diameter
On factory coils, the wire diameter is indicated along with other parameters. But what if the wire is taken from a stranded wire cut? The wire diameter can be measured with a micrometer. But even if there is no micrometer, you can use the old-fashioned way - measure the diameter of the wire using a ruler or caliper. Let not so precisely, but for our case it is quite acceptable.
We take a ruler and wind on it from 10 to 20 turns. The recommended winding width is about a centimeter. At the same time, we try to ensure that the coils lie as tightly as possible. We consider how many millimeters our turns took and divide this number by the number of turns. It is not necessary to wind on the ruler, if the piece of wire is short, you can use a pencil, screwdriver, lighter or any other object to wind it. The main thing is that the turns are wound evenly and tightly.
For example, the width of the wound turns is 9 mm, with the number of turns 20. Dividing 9 by 20, we get that the diameter of the wire, if we discard another 0.05 mm for the gaps between the turns, is approximately 0.40 mm. With this wire, it will be possible to restore a 20 A fuse. That's so simple and pretty accurate!
And at the end of the video demonstrating the burnout of the fusible link:
Fuse- this is an installation product designed to protect electrical appliances by turning off the supply of electricity to them when the permissible current value is exceeded by melting the calibrated wire installed in the fuse.
Fuses are widely used to protect electrical wiring and expensive radio equipment from short circuits, surges in the supply network and ensure the safe operation of electrical appliances. They are produced in different designs, standard sizes and for any protection currents.
The considered fuse repair technology, subject to all conditions, will ensure its protective function. But not everyone has experience with a soldering iron and measuring wire diameter. And in any case, an industrial-made fuse will work more reliably.
Previously, residential electrical wiring was also protected exclusively with the help of fuses installed in traffic jams. Currently, more reliable reusable short circuit protection devices are used to protect electrical wiring - circuit breakers. In electrical appliances, more better protection from short circuits than a fuse has not yet come up with anything. The use of fuses in automobiles is especially important, since they are the only reliable and cheap means of protection against short circuits.
Conditional graphic designation
fuse
The conventional graphic designation of the fuse in the diagrams is similar to the resistance designations, and differs only in that the line passes through the middle of the rectangle without breaking. Next to the symbol is usually written and letter designation Etc. or F. Sometimes they just write thermal fuse or fuse on the diagrams. After the letter, the fuse protection current is often indicated, for example F 1 A, which means that a fuse is installed in the circuit for a protection current of 1 ampere.
During operation, the fuses fail, and they must be replaced with new ones. It is believed that fuses cannot be repaired. But if the matter of repair is approached competently, then almost any fuse can be successfully repaired and reused. After all, the fuse case remains intact, and only a thin calibrated wire located inside the case burns out. If the burnt wire is replaced with the same one, then the fuse can continue to serve.
The principle of operation of the fuse on the video
When passing electric current less than the maximum permissible, the calibrated wire connecting the fuse contacts heats up to a temperature of about 70 ° C. If the current of the fuse rating is exceeded, the wire starts to heat up more and when it reaches the melting point of the metal from which it is made, it melts, electrical circuit breaks and the current stops flowing.
Therefore, the fuse was called a fusible or fusible link. The video is presented in slow motion, in order to clearly see how the wire burns out in the fuse. In real conditions, the wire in the fuse burns out almost instantly.
The fuse protects against overcurrent in the circuit and, no matter the voltage of the supply network in which it is installed, it can be a 1.5 V battery, and car battery for 12 V or 24 V, AC 220 V, three-phase network at 380 V. That is, you can install the same fuse, for example, with a rating of 1 A and in the fuse box of the car, and in the flashlight and in the 380 V switchboard. All types of fuses differ only in appearance and design, and work according to the same principle - when given current in the circuit, the wire melts in the fuse due to heating.
There are two main reasons for the failure of the fuse, due to surges in the supply voltage or a breakdown inside the radio equipment itself. Rarely, but there are fuse failures due to its poor quality.
Many people think that the fuse cannot be repaired. But it is not so. In an emergency, when there is no spare at hand and, for example, because of a car on the road or an amplifier that refused to work, and the musical accompaniment of a school ball or wedding breaks down, and all the shops are already closed, you don’t have to choose.
With a competent approach, it is possible to successfully restore a blown fuse for temporary use before replacing it with a new one, while maintaining its protective functions. Often such problems are solved by simply closing the contacts of the fuse holder with any wire that comes across, and even worse, they simply insert a nail or a piece of thick wire instead of the fuse. Such a decision can completely ruin everything and contribute to the outbreak of fire.
Fuse types
By purpose and design, fuses are of the following types:
- Forklifts (mainly used to protect electrical wiring and appliances in cars);
- With low-current inserts for protecting electrical appliances with current consumption up to 6 amperes;
- Cork (installed in shields of residential buildings, designed for protection current up to 63 amperes);
- Knife (used in industry to protect networks at current consumption up to 1250 amperes);
- gas generating;
- Quartz.
The repair technology considered in the article is intended for the restoration of fork, with low-current inserts, cork and knife-type fuses.
Tubular Fuses
A tubular fuse is a glass or ceramic tube, closed at the ends with metal caps, which are interconnected by a wire calibrated in diameter, passing inside the tube. Appearance tubular fuses you see in the photo.
The wire is welded to the caps spot welding or soldered. In fuses designed for very high currents, the cavity inside the tube is often filled with quartz sand.
Automotive Fuses
Fuses in cars rarely fail. Usually only in cases where the equipment fails. Most often when the headlight bulbs burn out. The fact is that when the incandescent filament at the light bulb breaks, a Voltaic arc is formed, the filament burns out and becomes shorter, the resistance decreases sharply and the current increases many times over.
It happens that the fuse in the car burns out when the wipers are jammed. Less often with short circuits in the wiring. In the photo you see widely used automotive blade (fork) type fuses. Under each fuse is the protection current in amperes.
A blown fuse in a car should be replaced with a fuse of the same rating, but it can also be repaired by replacing the wire blown in the fuse with a copper wire of the appropriate diameter. The voltage of the car's on-board network does not matter. The main thing is the compliance of the protection current. If it is difficult to determine the value of a blown auto fuse, then you can use the color coding.
Automotive fuse color coding
Formula for Calculating Fuse Wire Diameter
according to the power of the electrical appliance
Power is often indicated on labels glued to products. If the power consumption is indicated on the product, you can calculate the rated current of the fuse using the formula below.
where I nom is the rated current of the fuse protection, A; P max is the maximum load power, W; U- supply voltage, V. But it is much more convenient to use ready-made data from tables. Please note that the first table is used to select the fuse rating for products powered by a 220 V household electrical network, and the second one is for products used in vehicles with an on-board network voltage of 12 V.
Table for selecting the fuse rating depending on the power consumption of the electrical appliance at a supply voltage of 220 V
Consider an example of how to choose a fuse.
The TV stopped working after a thunderstorm. It is determined that the fuse has blown. Its denomination is not known. On the label back cover it is written that the power consumption is 120 W, it happens that they also write 120 VA. This is the designation of the same power, but according to the standards of different countries. According to the table, it turns out that for electrical appliances with a maximum power consumption of 120 W (the closest value is 150 W) there is a 1 A fuse.
The method for selecting a fuse to protect the vehicle's on-board electrical wiring is no different from choosing a 220 V household electrical wiring.
Table for selecting the fuse rating depending on the power consumption of the electrical appliance at a supply voltage of 12 V (car on-board network)
If, after two replacements, the fuses blow each time, it means that the appliance is damaged and it needs to be repaired. An attempt to install a fuse for a higher current can only cause additional damage to the product, up to the point of being unrepairable.
Fuse Current Calculator
If the tables do not contain data for your case, for example, the supply voltage of the product is 24 V or 110 V, then you can independently perform the calculation using the online calculator below.
When calculating on a calculator, you will get the exact current value. For reliable operation of the fuse, it is necessary that its rating be at least 5% larger. For example, if a calculated current value of 1 A is obtained, then you need to take a fuse of the largest nearest rating from the standard range, that is, 2 A.
Sometimes attempts to determine the fuse rating by reading information fail. There are no inscriptions on the electrical appliance, the marking on the fuse is not readable. If you have an ammeter and experience with it, then by removing the fuse and connecting the ammeter to the contacts of the block in which the fuse was installed, you can measure the current and thereby determine its rating.
But there is a pitfall here. If the fuse has failed due to a malfunction of the electrical appliance, then the current can be much higher than it should be, in addition, the measuring device can also be disabled.
Fuse Wire Diameter Calculation
To repair the fuse, it is necessary to replace the blown wire. In the production of fuses, factories use, depending on the magnitude of the current and speed, calibrated silver, copper, aluminum, nickel, tin, lead and other metal wires.
For the manufacture of a fuse at home, only red copper of a calibrated diameter is available. All electrical wires are made of copper, and the more elastic the wire, the thinner the conductors in it and the greater their number. Therefore, the entire technology proposed below is focused on the use of copper wire.
When choosing a fuse for equipment, developers use a simple law. The fuse current must be greater than the maximum consumed product. For example, if the maximum current consumption of the amplifier is 5 amps, then the fuse is selected for 10 amps. The first thing you need to find on the fuse box is its marking, from which you can find out what current it is rated for. Often the current value is written on the product case, next to the fuse installation site. Then, from the table below, determine what diameter the wire is needed.
Tables for selecting wire diameter
depending on fuse protection current
For repair of fuses for protection current from 0.25 to 50 amperes
| 0,25 | 0.5 | 1.0 | 2.0 | 3.0 | 5.0 | 7.0 | 10.0 | 15.0 | 20.0 | 25.0 | 30.0 | 35.0 | 40.0 | 45.0 | 50.0 | ||
| Wire diameter, mm | Copper | 0.02 | 0.03 | 0.05 | 0.09 | 0.11 | 0.16 | 0.20 | 0.25 | 0.33 | 0.40 | 0.46 | 0.52 | 0.58 | 0.63 | 0.68 | 0.73 |
| Aluminum | - | - | 0.07 | 0.10 | 0.14 | 0.19 | 0.25 | 0.30 | 0.40 | 0.48 | 0.56 | 0.64 | 0.70 | 0.77 | 0.83 | 0.89 | |
| Steel | - | - | 0.32 | 0.20 | 0.25 | 0.35 | 0.45 | 0.55 | 0.72 | 0.87 | 1.00 | 1.15 | 1.26 | 1.38 | 1.50 | 1.60 | |
| Tin | - | - | 0.18 | 0.28 | 0.38 | 0.53 | 0.66 | 0.85 | 1.02 | 1.33 | 1.56 | 1.77 | 1.95 | 2.14 | 2.30 | 2.45 | |
For repair of fuses for protection current from 60 to 300 Amperes
| Fuse protection current, Amp | 60 | 70 | 80 | 90 | 100 | 120 | 160 | 180 | 200 | 225 | 250 | 275 | 300 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wire diameter, mm | Copper | 0.83 | 0.91 | 1.00 | 1.08 | 1.16 | 1.31 | 1.59 | 1.72 | 1.84 | 1.99 | 2.14 | 2.28 | 2.41 |
| Aluminum | 1.00 | 1.10 | 1.22 | 1.32 | 1.42 | 1.60 | 1.94 | 2.10 | 2.25 | 2.45 | 2.60 | 2.80 | 2.95 | |
| Steel | 1.80 | 2.00 | 2.20 | 2.38 | 2.55 | 2.85 | 3.20 | 3.70 | 4.05 | 4.40 | 4.70 | 5.0 | 5.30 | |
| Tin | 2.80 | 3.10 | 3.40 | 3.65 | 3.90 | 4.45 | 4.90 | 5.80 | 6.20 | 6.75 | 7.25 | 7.70 | 8.20 | |
Formula for calculating the diameter of copper wire
for fuse
To determine more accurate copper wire diameters for repairing a fuse, or if a fuse is required for a protection current that is not in the table, you can use the formula below.
where I pr - fuse protection current, A; d– copper wire diameter, mm. How to measure wire diameter
The diameter of thin wire is best measured with a micrometer. If there is no micrometer at hand to measure the diameter of the wire, then you can use an ordinary ruler.
It is necessary to wind 10-20 turns to a turn of wire on a ruler, divide the number of closed millimeters by the number of wound turns. Get the diameter. For example, I have 10 turns of wire wound, and they covered 6.5 mm. Divide 6.5 by 10. The wire diameter is 0.65 mm. 0.05 mm is occupied by insulation. Therefore, the real diameter is 0.6 mm.
Such a wire is suitable for making a 30 A fuse. The wire was wound thick for greater clarity. The more turns you wind on the ruler, the more accurate the measurement result will be. It is necessary to wind at least one centimeter. If a short wire is available, then wind it around any rod, for example, a screwdriver, toothpick or pencil, and measure the width of the winding with a ruler.
You can process the measurement results using the online calculator. To determine the diameter of the wire, it is enough to enter the winding width, the number of turns in the windows and click "Calculate wire diameter".
Do-it-yourself fuse repair
Tube Fuse Repair
The first one is the easiest. The wire is stripped to a shine and wound on each cup several turns, then the fuse is inserted into the holder. This method is not reliable, and you can use it as a temporary measure. Due to its simplicity, it allows you to quickly check the health of the electrical appliance. If the wire melted when turned on, then it is not a fuse, and a more qualified repair is required.
The second way is somewhat more complicated. But also does not require the use of soldering. It is necessary to warm the cups in turn with a lighter or on gas stove and holding through the fabric with your hands remove them from the glass tube. You can also heat with a soldering iron. Inside the cup for good contact must be thoroughly cleaned of adhesive residue.
Pass the stripped wire through the tube diagonally, bend its ends along the tube and put the cups in place. The fuse has been repaired.
The third method is essentially the same as the first two. But the repaired fuse is practically no different from the new one. Repair is carried out as follows.
The factory calibrated wire in the manufacture of the fuse is threaded into the holes in the ends of the cups and fixed with solder. In order to insert a new wire, it is necessary to heat the ends of the cups with a soldering iron and free the holes in the ends of the cups from the solder with a toothpick or a sharpened wooden stick. Then carry out the factory operation described above.
There are holes in the cups of very small diameter and it is difficult to clean them from solder. Then if there is technical feasibility it is easier to drill holes with a drill with a diameter of 1-2 mm or expand with a faceted awl
The proposed technology for repairing fuses and fuse links can be successfully applied to repair almost any type of fuses.
Repair of a knife type car fuse
The technology for repairing an automobile fuse is no different from the technology for repairing a tubular fuse, it is even simpler, since there is no need to disassemble it.
First you need to clean the fuse knives at its base with a strip of several millimeters with sandpaper or a needle file and tin these places with solder.
When tinning, I encountered the fact that when using alcohol-rosin flux, the solder did not want to spread over the surface of the knives. I had to use the FIM flux, designed for soldering copper, silver, constantan, platinum and ferrous metals. The basis of the flux is phosphoric acid. I always use it for soldering if the rosin is not suitable. FIM flux residues are removed by washing with water.
The fuse was designed for a protection current of 10 A, therefore, in accordance with the table above, a ⌀0.25 mm wire was taken for repair. The wire was shaped like a loop, as shown in the photograph, and its ends were tinned with solder.
After all the preparatory work, it remains only to bring a loop of wire inside the fuse case and solder the ends to the legs.
Spreading solder can be cut with a knife, removed with sandpaper or filed off.
The car fuse has been repaired and can now be reused to protect circuits in car wiring. If, after installing the repaired fuse, it blows again, then you need to look for a malfunction in the electrical equipment of the car.
How to make a DIY fuse blown indicator
On sale there are automotive fuses with an indicator of their failure. A miniature incandescent bulb or LED is mounted in the fuse case, which starts to glow when the fuse blows. Such an auto fuse blown indicator can be assembled with your own hands according to the electrical circuit shown below in the photo.
To do this, it is enough to connect any VD1 LED in parallel with the fuse contacts through a current-limiting resistor R1 or a miniature light bulb rated for 12 V. The fuse blown indicator can be mounted both in the fuse box and mounted on its holder block. The second option is preferable, since when replacing the fuse, the indicator will remain in place. The indicator will not light if the fuse is blown, if no load is connected.
The diagram of the fuse blown indicator or circuit breaker operation shown in the photo can also successfully work in a household electrical network with a supply voltage of 220 V.
It is enough to increase the value of the resistor R1 to 300-500 kOhm and to protect the VD1 LED from reverse voltage breakdown, supplement the circuit with a VD2 diode of any type, designed for a reverse voltage of at least 300 V. Suitable, for example, widely used domestic diode KD109B or imported 1N4004.
For AC 220 V, you can make a blown fuse or circuit breaker indicator on a neon light bulb.
