Wiring in modern apartments provides for a maximum operating current in the network up to 25 Amperes. Under this parameter, and circuit breakers installed in the switchboard of the apartment. The cross section of the wire at the entrance to the room must be at least 4 mm2. When installing internal wiring, it is permissible to use cables with a cross section of 2.5 mm2, which are rated for a current of 16 Amperes.
[ Hide ]
Wire diameter measurement
According to the standard, the wire diameter must correspond to the declared parameters, which are described in the marking. But the actual size may differ from the declared one by 10-15 percent. This is especially true for cables that are manufactured by small firms, but large manufacturers can also have problems. Before buying an electrical wire for transmitting high currents, it is recommended to measure the diameter of the conductor. For this, they can be used various ways, differing in error. Before performing the measurement, it is required to clean the cable cores from insulation.
Measurements can be made directly in the store if the seller allows you to remove the insulation from a small section of the wire. Otherwise, you will have to purchase a small piece of cable and measure on it.
Micrometer
Maximum accuracy can be obtained using micrometers, which have a mechanical and electronic circuit. The tool shaft has a scale with a division value of 0.5 mm, and on the circle of the drum there are 50 marks with a division value of 0.01 mm. The characteristics are the same for all models of micrometers.
When working with a mechanical device, follow the sequence of actions:
- By rotating the drum, the gap between the screw and the heel is set close to the measured size.
- Bring the screw with a ratchet closer to the surface of the part to be measured. The eyeliner is performed by hand rotation without effort until the ratchet is activated.
- Calculate the transverse diameter of the part according to the readings on the scales placed on the stem and drum. The product diameter is equal to the sum of the value on the rod and the drum.
Measuring with a mechanical micrometer
Working with an electronic micrometer does not require rotation of the nodes, it displays the diameter value on the LCD screen. It is recommended to check the settings before using the instrument, as electronic devices measured in millimeters and inches.
Caliper
The device has a reduced accuracy compared to a micrometer, which is quite enough to measure the conductor. Calipers are equipped with a flat scale (vernier), a circular dial or digital indication on a liquid crystal display.
To measure the transverse diameter, you must:
- Clamp the measured conductor between the jaws of the caliper.
- Calculate the value on the scale or view it on the display.
An example of calculating the size on a vernier
Ruler
Measuring with a ruler gives a rough result. To perform the measurement, it is recommended to use tool rulers, which have greater accuracy. The use of wooden and plastic school products will give a very approximate diameter.
To measure with a ruler, you need:
- Strip a piece of wire with a length of up to 100 mm from insulation.
- Wrap the resulting segment tightly around a cylindrical object. The turns must be complete, that is, the beginning and end of the wire in the winding are directed in the same direction.
- Measure the length of the resulting winding and divide by the number of turns.
Measuring the diameter with a ruler by the number of turns
In the example above, there are 11 turns of wire that are about 7.5mm long. By dividing the length by the number of turns, you can determine the approximate value of the diameter, which in this case is 0.68 mm.
On the websites of stores selling electrical wires, there are online calculators that allow you to calculate the cross section by the number of turns and the length of the resulting spiral.
Definition of section by diameter
After determining the diameter of the wire, you can begin to calculate the cross-sectional area in squares (mm2). For cables of the VVG type, consisting of three single-core conductors, calculation methods are used according to the formula or according to the prepared table of correspondence between diameters and areas. The methods are also applicable to products with other markings.
According to the formula
The main way is to calculate according to the formula of the form - S \u003d (p / 4) * D2, where π \u003d 3.14, and D is the measured diameter. For example, to calculate the area with a diameter of 1 mm, you need to calculate the value: S=(3.14/4)*1²=0.785 mm2.
Online calculators are available on the network that allow you to calculate the area of \u200b\u200ba circle by diameter. Before buying a cable, it is recommended to calculate the values in advance, summarize them in a table and use it in the store.
The video from user Alexander Kvasha demonstrates checking the cross section of the wire cores.
According to the table with common diameters
To simplify the calculation, it is convenient to use the finished table.
The order of using numbers from the table:
- Select the type of wire that you intend to purchase, for example, VVG 3 * 4.
- Determine the diameter according to the table - a section of 4 mm2 corresponds to a diameter of 2.26 mm.
- Check the actual value of the wire diameter. In case of a match, products can be purchased.
Below is a table of the ratio of the sections of the main types of copper wiring to diameters and current (at a voltage of 220 V).
An additional criterion for matching the cross section to the diameter is the weight of the wire. The method of determining the diameter by weight is used when checking thin wire for winding transformers. The thickness of products starts from 0.1 mm, and it is problematic to measure it with a micrometer.
Brief table the correspondence of vein diameters by weight is given below. Detailed data is available in stores specializing in the sale of electronic components.
| Diameter, mm | Section, mm2 | Weight, g/km |
| 0,1 | 0,0079 | 70 |
| 0,15 | 0,0177 | 158 |
| 0,2 | 0,0314 | 281 |
| 0,25 | 0,0491 | 438 |
| 0,3 | 0,0707 | 631 |
| 0,35 | 0,0962 | 859 |
| 0,4 | 0,1257 | 1,122 |
When calculating the wire diameter for fuses, the material of the conductor must be taken into account. A brief table of correspondence between cable diameters from common types of material and current strength is given below.
| Break current, A | Copper | Aluminum | Nickelin | Iron | Tin | Lead |
| 0,5 | 0,03 | 0,04 | 0,05 | 0,06 | 0,11 | 0,13 |
| 1 | 0,05 | 0,07 | 0,08 | 0,12 | 0,18 | 0,21 |
| 5 | 0,16 | 0,19 | 0,25 | 0,35 | 0,53 | 0,60 |
| 10 | 0,25 | 0,31 | 0,39 | 0,55 | 0,85 | 0,95 |
| 15 | 0,32 | 0,40 | 0,52 | 0,72 | 1,12 | 1,25 |
| 25 | 0,46 | 0,56 | 0,73 | 1,00 | 1,56 | 1,75 |
| 50 | 0,73 | 0,89 | 1,15 | 1,60 | 2,45 | 2,78 |
| 100 | 1,15 | 1,42 | 1,82 | 2,55 | 3,90 | 4,40 |
| 200 | 1,84 | 2,25 | 2,89 | 4,05 | 6,20 | 7,00 |
| 300 | 2,40 | 2,95 | 3,78 | 5,30 | 8,20 | 9,20 |
For stranded cable
The diameter of a multi-core cable is determined by the cross-sectional size of one conductor multiplied by their number. The main problem is measuring the diameter of a thin wire.
An example is a cable consisting of 25 cores with a diameter of 0.2 mm. According to the above formula, the cross section is: S \u003d (3.14 / 4) * 0.2² \u003d 0.0314 mm2. With 25 cores, it will be: S=0.0314*25=0.8 mm2. Then, according to the correspondence tables, it is determined whether it is suitable for transmitting the current of the required strength or not.
Another way to approximate current strength is to multiply the diameter of a stranded cable by a correction factor of 0.91. The coefficient provides for the non-monolithic structure of the wire and the air gaps between the turns. Measurement of the outer diameter is carried out with little effort, since the surface is easily deformed and the cross section becomes oval.
When calculating the segment part of the cable, formulas or tabular values are used. The table shows the standard values for the width and height of the segment.
Photo gallery
Segment cable (far right) 
cable segment
Table of power consumption of electrical appliances
A common way to determine the required wire cross-section is the peak power calculation method. In order to find out the load, you can use the standard table, which summarizes the parameters of power and peak current consumption for household appliances.
| Device type | power, kWt | Peak current, A | Consumption mode |
| standard incandescent lamp | 0,25 | 1,2 | Constant |
| Kettle with electric heater | 2,0 | 9,0 | Short term up to 5 minutes |
| Electric stove with 2-4 burners | 6,0 | 60,0 | |
| Microwave | 2,2 | 10,0 | Periodic |
| Meat grinder with electric drive | Similarly | Similarly | Depends on the intensity of use |
| Toaster | 1,5 | 7,0 | Constant |
| Electric coffee grinder | 1,5 | 8,0 | Depends on the intensity of use |
| Grill | 2,0 | 9,0 | Constant |
| Coffee maker | 1,5 | 8,0 | Constant |
| Separate electric oven | 2,0 | 9,0 | Depends on the intensity of use |
| Dishwashing machine | 2,0 | 9,0 | Periodic (for the period of operation of the heater) |
| Washing machine | 2,0 | 9,0 | Similarly |
| Dryer | 3,0 | 13,0 | Constant |
| Iron | 2,0 | 9,0 | Periodic (for the period of operation of the heating coil) |
| Vacuum cleaner | Similarly | Similarly | Depends on the intensity of use |
| Oil heater | 3,0 | 13,0 | Similarly |
| hair dryer | 1,5 | 8,0 | Similarly |
| air conditioner | 3,0 | 13,0 | Similarly |
| Computer system unit | 0,8 | 3,0 | Similarly |
| Electric motor driven tools | 2,5 | 13,0 | Similarly |
The current will be consumed by the refrigerator, electrical appliances in standby state (TVs, radio telephones), charging device. The total value of power consumption by devices is considered within 0.1 kW.
When connecting all available household appliances, the current can reach 100-120 A. This connection option is unlikely, therefore, when calculating the load, common connection combinations are taken into account.
For example, in the morning you can use:
- electric kettle - 9.0 A;
- microwave oven - 10.0 A;
- toaster - 7 A;
- coffee grinder or coffee maker - 8 A;
- other Appliances and lighting - 3 A.
The total consumption of devices can reach: 9 + 10 + 7 + 8 + 3 = 37 A. There are also calculators that allow you to calculate the current from the power consumption and voltage.
Cable selection according to the tables of maximum current in the network
Two types of data from the table above are used for the calculation:
- by total power;
- by the amount of current consumed by the devices.
There are tables of standard values that allow you to determine the required diameter and cross section, which are then checked on the purchased wire. The found indicator is rounded up to match the actual cable diameter.
In residential premises, wires with an excessive cross section should not be used, since they have a large resistance, which leads to a voltage drop.
For copper cable
To calculate the copper conductor, a table compiled for a voltage of 230 V is used.
| power, kWt | Current, A | ||||
| 0,1 | 0,43 | 0,09 | 0,33 | 0,11 | 0,37 |
| 0,5 | 2,17 | 0,43 | 0,74 | 0,54 | 0,83 |
| 1,0 | 4,35 | 0,87 | 1,05 | 1,09 | 1,18 |
| 2,0 | 8,70 | 1,74 | 1,49 | 2,17 | 1,66 |
| 3,0 | 13,04 | 2,61 | 1,82 | 3,26 | 2,04 |
| 4,0 | 17,39 | 3,48 | 2,10 | 4,35 | 2,35 |
| 5,0 | 21,74 | 4,35 | 2,35 | 5,43 | 2,63 |
| 8,0 | 34,78 | 6,96 | 3,16 | 9,78 | 3,53 |
| 10,0 | 43,48 | 8,7 | 3,33 | 10,87 | 3,72 |
For aluminum cable
The table below can be used to calculate an aluminum wire (data taken for a voltage of 230 V).
| power, kWt | Current, A | Area (with external wiring), mm2 | Diameter (with external wiring), mm | Area (at hidden wiring), mm2 | Diameter (with hidden wiring), mm |
| 0,1 | 0,43 | 0,12 | 0,40 | 0,14 | 0,43 |
| 0,5 | 2,17 | 0,62 | 0,89 | 0,72 | 0,96 |
| 1,0 | 4,35 | 1,24 | 1,26 | 1,45 | 1,36 |
| 2,0 | 8,70 | 2,48 | 1,78 | 2,90 | 1,92 |
| 3,0 | 13,04 | 3,73 | 2,18 | 4,35 | 2,35 |
| 4,0 | 17,39 | 4,97 | 2,52 | 5,80 | 2,72 |
| 5,0 | 21,74 | 6,21 | 2,81 | 7,25 | 3,04 |
| 8,0 | 34,78 | 9,94 | 3,56 | 11,59 | 3,84 |
| 10,0 | 43,48 | 12,42 | 3,98 | 14,49 | 4,30 |
Cable selection according to the PUE and GOST tables
When buying a wire, it is recommended to look at the GOST standard or the conditions of the technical specifications according to which the product is made. GOST requirements are higher than similar parameters specifications, therefore, products made according to the standard should be preferred.
Tables from the rules for the installation of electrical installations (PUE) represent the dependence of the strength of the current transmitted through the conductor on the cross section of the core and the method of laying in the main pipe. The permissible current decreases as the individual cores increase or the use of a multi-core cable in insulation. The phenomenon is associated with a separate paragraph in the PUE, which specifies the parameters of the maximum allowable heating of the wires. The main pipe is understood as a box, including plastic or when laying the wiring in a bundle on a cable tray.
In theory, the diameter of the conductors should correspond to the declared parameters. For example, if it is indicated on the marking that the cable is 3 x 2.5, then the cross section of the conductors must be exactly 2.5 mm 2. In fact, it turns out that the real size can differ by 20-30%, and sometimes more. What does it threaten? Overheating or melting of insulation with all the ensuing consequences. Therefore, before buying, it is advisable to find out the size of the wire in order to determine its cross section. How exactly to calculate the cross section of the wire in diameter and we will find out further.
How and with what to measure the diameter of the wire (wire)
To measure the diameter of the wire, a caliper or micrometer of any type (mechanical or electronic) is suitable. It is easier to work with electronic ones, but not everyone has them. It is necessary to measure the core itself without insulation, therefore first move it away or remove a small piece. This can be done if the seller allows. If not, buy a small piece for testing and take measurements on it. On a conductor that has been stripped of insulation, measure the diameter, after which you can determine the actual cross-section of the wire according to the dimensions found.
Which measuring device is better in this case? If speak about mechanical models, then a micrometer. It has higher measurement accuracy. If we talk about electronic options, then for our purposes they both give quite reliable results.
If you don't have a caliper or micrometer, take a screwdriver and a ruler with you. You will have to strip a pretty decent piece of the conductor, so this time you are unlikely to do without buying a test sample. So, remove the insulation from a piece of wire 5-10 cm. Wind the wire around the cylindrical part of the screwdriver. The coils are laid close to each other, without a gap. All turns must be complete, that is, the "tails" of the wire must stick out in one direction - up or down, for example.
The number of turns is not important - about 10. It can be more or less, it's just easier to divide by 10. Count the turns, then apply the resulting winding to the ruler, aligning the beginning of the first turn with zero mark(as in the photo). Measure the length of the section occupied by the wire, then divide it by the number of turns. Get the wire diameter. It's that simple.
For example, let's calculate the size of the wire shown in the photo above. The number of turns in this case is 11, they occupy 7.5 mm. We divide 7.5 by 11, we get 0.68 mm. This will be the diameter of this wire. Next, you can search for the cross section of this conductor.
We are looking for a wire cross-section by diameter: formula
The wires in the cable are circular in cross section. Therefore, in the calculations we use the formula for the area of a circle. It can be found using either the radius (half of the measured diameter) or the diameter (see formula).
Determine the cross section of the wire by diameter: formula
For example, let's calculate the cross-sectional area of the conductor (wire) according to the size calculated earlier: 0.68 mm. Let's use the radius formula first. First we find the radius: we divide the diameter by two. 0.68 mm / 2 = 0.34 mm. Next, we substitute this number into the formula
S \u003d π * R 2 \u003d 3.14 * 0.34 2 \u003d 0.36 mm 2
It is necessary to count as follows: first we square 0.34, then we multiply the resulting value by 3.14. We got the cross section of this wire 0.36 square millimeters. This is a very thin wire that is not used in power networks.
Let's calculate the cable cross-section by diameter using the second part of the formula. It should be exactly the same value. The difference may be in thousandths due to different rounding.
S \u003d π / 4 * D 2 \u003d 3.14 / 4 * 0.68 2 \u003d 0.785 * 0.4624 \u003d 0.36 mm 2
In this case, we divide the number 3.14 by four, then square the diameter, multiply the two resulting numbers. We get a similar value, as it should be. Now you know how to find out the cable cross-section by diameter. Whichever of these formulas is more convenient for you, use that one. No difference.
Correspondence table for wire diameters and their cross-sectional area
It is not always desirable or possible to carry out calculations in a store or in the market. In order not to waste time on calculations or not to make a mistake, you can use the table of wire diameters and cross-sections, which contains the most common (standard) sizes. You can write it down, print it out and take it with you.
| Conductor diameter | Conductor cross section |
|---|---|
| 0.8 mm | 0.5 mm2 |
| 0.98 mm | 0.75 mm2 |
| 1.13 mm | 1 mm2 |
| 1.38 mm | 1.5 mm2 |
| 1.6 mm | 2.0 mm2 |
| 1.78 mm | 2.5 mm2 |
| 2.26 mm | 4.0 mm2 |
| 2.76 mm | 6.0 mm2 |
| 3.57 mm | 10.0 mm2 |
| 4.51 mm | 16.0 mm2 |
| 5.64 mm | 25.0 mm2 |
How to work with this table? As a rule, the cables have a marking or a tag on which its parameters are indicated. It indicates the cable marking, the number of cores and their cross section. For example, 2x4. We are interested in the parameters of the core, and these are the numbers that come after the “x” sign. In this case, it is stated that there are two conductors having a cross section of 4 mm 2 . So we will check whether this information is true.
How to work with a table
To check, measure the diameter using any of the methods described, then refer to the table. It states that with such a cross section of four square millimeters, the wire size should be 2.26 mm. If your measurements are the same or very close (the measurement error exists, since the devices are not ideal), everything is fine, you can buy this cable.
But much more often, the actual diameter of the conductors is much less than the declared one. Then you have two ways: look for a wire from another manufacturer or take a larger section. Of course, you will have to overpay for it, but the first option will require a fairly long period of time, and it’s not a fact that you will be able to find a cable that meets GOST.
The second option would require more money, since the price significantly depends on the declared section. Although, not a fact - a good cable, made according to all standards, can cost even more. This is understandable - the cost of copper, and, often, for insulation, subject to technology and standards, is much higher. Therefore, manufacturers are cunning, reducing the diameter of the wires - in order to reduce the price. But such savings can turn into disaster. So be sure to take measurements before buying. Even trusted suppliers.
And one more thing: inspect and feel the insulation. It should be thick, solid, have the same thickness. If, in addition to changing the diameter, there are also problems with insulation, look for a cable from another manufacturer. In general, it is desirable to find products that meet the requirements of GOST, and not made according to TU. In this case, there is hope that the cable or wire will last a long time and without problems. Today this is not easy to do, but if you breed or, quality is very important. That's why it's probably worth looking into.
How to determine the cross section of a stranded wire
Sometimes conductors are used stranded - consisting of many identical thin wires. How to calculate the wire cross-section by diameter in this case? Yes, exactly the same. Take measurements / calculations for one wire, count their number in a bundle, then multiply by this number. So you will find out the cross-sectional area of \u200b\u200ba stranded wire.
In practice, it is often necessary to calculate the resistance of various wires. This can be done using formulas or according to the data given in Table. one.
The influence of the conductor material is taken into account using the resistivity, denoted by the Greek letter? and representing a length of 1 m and a cross-sectional area of 1 mm2. The smallest resistivity? \u003d 0.016 Ohm mm2 / m has silver. Let us give the average value of the specific resistance of some conductors:
Silver - 0.016 , Lead - 0.21, Copper - 0.017, Nickel - 0.42, Aluminum - 0.026, Manganine - 0.42, Tungsten - 0.055, Constantan - 0.5, Zinc - 0.06, Mercury - 0.96, Brass - 0.07, Nichrome - 1.05, Steel - 0.1, Fekhral - 1.2, Phosphorous bronze - 0.11, Khromal - 1.45.With different amounts of impurities and with different ratios of the components that make up the rheostat alloys, resistivity may change somewhat.
The resistance is calculated by the formula:
where R - resistance, Ohm; resistivity, (Ohm mm2)/m; l - wire length, m; s is the cross-sectional area of the wire, mm2.
If the wire diameter d is known, then its cross-sectional area is:
It is best to measure the diameter of the wire with a micrometer, but if it is not available, then wrap tightly 10 or 20 turns of wire on a pencil and measure the length of the winding with a ruler. Dividing the length of the winding by the number of turns, we find the diameter of the wire.
To determine the length of a wire of known diameter from a given material, necessary to obtain the desired resistance, use the formula
Table 1.
Note. 1. Data for wires not listed in the table must be taken as some average values. For example, for a nickeline wire with a diameter of 0.18 mm, we can approximately assume that the cross-sectional area is 0.025 mm2, the resistance of one meter is 18 ohms, and the allowable current is 0.075 A.
2. For a different current density value, the data of the last column must be changed accordingly; for example, at a current density of 6 A/mm2, they should be doubled.
Example 1. Find the resistance of 30 m copper wire with a diameter of 0.1 mm.
Decision. We determine according to the table. 1 resistance of 1 m of copper wire, it is equal to 2.2 ohms. Therefore, the resistance of 30 m of wire will be R = 30 2.2 = 66 ohms.
Calculation by formulas gives the following results: wire cross-sectional area: s= 0.78 0.12 = 0.0078 mm2. Since the resistivity of copper is 0.017 (Ohm mm2) / m, we get R \u003d 0.017 30 / 0.0078 \u003d 65.50m.
Example 2. How much nickel wire with a diameter of 0.5 mm is needed to make a rheostat with a resistance of 40 ohms?
Decision. According to the table 1 we determine the resistance of 1 m of this wire: R = 2.12 Ohm: Therefore, in order to make a rheostat with a resistance of 40 Ohm, you need a wire whose length is l = 40 / 2.12 = 18.9 m.
Let's do the same calculation using the formulas. We find the cross-sectional area of the wire s \u003d 0.78 0.52 \u003d 0.195 mm2. And the length of the wire will be l \u003d 0.195 40 / 0.42 \u003d 18.6 m.
In order to successfully buy a wire, before buying it is necessary measure wire diameter Otherwise, you may become a victim of fraud. You will also have to measure the cross section of the wire if you add a new electrical point to the old wiring, since there may not be letter markings on it. The information below will help you choose the right technique. wire diameter measurement and use it effectively in practice.
At the same time, you will immediately have a question: “What is the point of a company to spoil its reputation?” There may be several explanations for this: But the whole point is that even after correct calculations wire gauge, you may still run into a problem despite the fact that you buy wire with suitable diameter. An accident can occur due to the fact that the conductor section will be indicated on the wire marking, which does not correspond to the actual one. This may happen as a result of the fact that the manufacturing plant saved on the material, or the company that produces this product did not comply with all the characteristics of the product. Also on the shelves you can find wires on which there is no marking at all, which initially makes one doubt their quality.
1. In order to save money. For example, the factory made wire diameter less than 2 mm. sq. with a 2.5 mm core, which made it possible to win on one running meter several kilograms of metal, not to mention the profit in mass production.
2. As a result of great competition, the company reduces the price of electrical wiring, trying to lure the majority of consumers to itself. Naturally, this happens due to wire diameter reduction which cannot be determined with the naked eye.
Both the first and second options take place in the sales market, so you better play it safe and make accurate calculations yourself, which will be discussed further.
Three main ways to determine the diameter of the wire.
There are several ways, but each of them is based on determination of diameters veins with subsequent calculations of the final results.
Method one. With the help of appliances. Today, there are a number of devices that help measure wire diameter or strands of wire. This is a micrometer and caliper, which are both mechanical and electronic (see below).
This option is primarily suitable for professional electricians who are constantly involved in the installation of electrical wiring. The most accurate results can be obtained with a caliper. This technique has the advantage that it is possible measure wire diameter even on a section of a working line, for example, in a socket.
After you have measured wire diameter, it is necessary to carry out calculations according to the following formula:
It must be remembered that the number "Pi" is 3.14, respectively, if we divide the number "Pi" by 4, we can simplify the formula and reduce the calculation to multiplying 0.785 by the diameter squared.
Method two. We use a line. If you decide not to spend money on the device, which is logical in this situation, then you can use a simple proven method to measure the cross section of a wire or wire ?. You will need a simple pencil, ruler and wire. Strip the core from the insulation, wind it tightly onto a pencil, and then measure the total length of the winding with a ruler (as shown in the figure).
Then divide the length of the wound wire by the number of strands. The resulting value will be wire section diameter.
However, the following must be taken into account:
- the more cores you wind on a pencil, the more accurate the result will be, the number of turns should be at least 15;
- press the turns tightly against each other so that there is no free space between them, this will significantly reduce the error;
- take measurements several times (change the measurement side, the direction of the ruler, etc.). A few results obtained will help you again avoid a large error.
Pay attention to the cons this method measurements:
1. You can only measure the cross section of thin wires, since you can hardly wind a thick wire around a pencil.
2. To begin with, you will need to purchase a small piece of the product before making the main purchase.
The formula discussed above applies to all measurements.
Method three. We use a table. In order not to carry out calculations according to the formula, you can use a special table in which specified wire diameter? (in millimeters) and the cross section of the conductor (in square millimeters). Ready-made tables will give you more accurate results and save you a lot of time, which you do not have to spend on calculations.
|
Conductor diameter, mm |
Conductor cross section, mm 2 |
Chocolate biscuit: the secrets of cooking in a slow cooker and oven
Chemical composition and nutritional value
Apple chips at home
Braised cabbage with white beans, recipe
How to reduce the ass, hips and stomach at home?