Diameter lived wires. Proper (accurate) measurement of cross sections of stranded power wires

In theory, the conductor diameter must comply with the declared parameters. For example, if it is indicated on the marking that the cable is 3 x 2.5, then the conductor cross section should be 2,5 mm 2. In fact, it turns out that the different size can differ by 20-30%, and sometimes more. What threatens it? Overheating or placing isolation with all the ensuing consequences. Therefore, before buying, it is desirable to find out the size of the wire to determine its cross section. How exactly consider the cross section of the wire in diameter and will find out further.

How and how to measure the diameter of the wire (wire)

To measure the diameter of the wire, the caliper or micrometer of any type (mechanical or electronic) is suitable. It is easier to work with electronic, but they are not all. It is necessary to measure the living well without isolation, therefore it is pre-moved it or remove the small piece. This can be done if the seller is allowed. If not, buy a small piece for testing and spend the measurements on it. On the insulation, the conductor measure the diameter, after which it is possible to determine the actual cross-section of the wire on the sizes.

What is the measuring device in this case better? If we talk about mechanical models, then micrometer. It has accuracy of measurements above. If we talk about electronic options, then for our purposes they both give quite reliable results.

If there is neither a caliper, nor micrometer, capture a screwdriver and a ruler. We have to clean a pretty decent piece of the conductor, so without buying a test pattern this time is hardly hampered. So, remove isolation from a piece of wires 5-10 cm. Wash the wire on the cylindrical part of the screwdriver. The coils are placed close one to another, without clearance. All turns must be complete, that is, the "tails" of the wires must be stitching in one direction - up or down, for example.

The number of turns is not important - about 10. It is possible more or less, just to divide it easier. Throwing turns, then apply the resulting winding to the ruler, aligning the beginning of the first turn with a zero mark (as in the photo). Measure the length of the area occupied by the wire, then it divides it to the number of turns. Get the wire diameter. That's so simple.

For example, we consider what 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 to 11, we get 0.68 mm. This will be the diameter of this wire. Next, you can search for the section of this conductor.

We are looking for a wire section in diameter: formula

Wires in the cable have a circle in cross section. Therefore, in the calculations, we use the formula of the area of \u200b\u200bthe circle. It can be found using radius (half of the measured diameter) or diameter (see formula).

Determine the cross section of the wire in diameter: formula

For example, we calculate the cross-sectional area of \u200b\u200bthe conductor (wire) in size calculated earlier: 0.68 mm. Let's first use the formula with a radius. First we find a radius: we divide the diameter for two. 0.68 mm / 2 \u003d 0.34 mm. Next this figure we substitute in the formula

S \u003d π * R 2 \u003d 3,14 * 0.34 2 \u003d 0.36 mm 2

It is necessary to count this way: first we will be erected into a square 0.34, then multiply the value obtained by 3.14. Received a cross section of this wire 0.36 square millimeters. This is a very thin wire, which is not used in power networks.

Let's calculate the cable cross section in diameter using the second part of the formula. It should be exactly the same meaning. The difference can be in thousands of shares 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 to four, then we will be erected into a square, the two figures obtained with a variant. We get a similar value, as it should be. Now you know how to find out the cable cross section in diameter. Which of these formulas are more convenient for you, that and use. No difference.

Table matching the diameters of the wires and their cross-section area

Conduct settlements in the store or in the market does not always want or have the opportunity. In order not to spend time on calculations or not mistaken, you can use the table of conformity of diameters and sections of the wires in which there are the most common (regulatory) dimensions. It can be rewritten, print and capture with you.

Conductor diameter	Conductor 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, on cables there is a marking or tag on which its parameters are indicated. There is a cable marking, the amount of lived and their cross section. For example, 2x4. We are interested in the parameters of the veins. And these are numbers that stand after the sign "x". In this case, it is stated that there are two conductor 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 of any of the described methods, then refer to the table. It indicates that with such a section in four square millimeters, the size of the wire must be 2.26 mm. If you have the same or very close measurements (measurement error exists, as non-ideal instruments), everything is fine, you can buy this cable.

But much more often the actual diameter of the conductors is significantly less than the stated. Then you have two ways: search for a wire of another manufacturer or take a larger cross section. For him, of course, you will have to overpay, but the first option will require a rather large period of time, and not the fact that you will be able to find the corresponding GOST cable.

The second option will require more money, since the price significantly depends on the declared section. Although, not a fact - a good cable made in all standards may be even more expensive. This is understandable - copper costs, and, often, and isolation, while compliance with technology and standards, is much larger. Therefore, manufacturers and chitryat, reducing the diameter of the wires - to reduce the price. But such savings can turn into trouble. So be sure to measure before purchasing. Even proven suppliers.

And also: inspect and swell insulation. It should be thick, solid, have the same thickness. If, in addition to changing the diameter, the problem is also with isolation - look for a cable of another manufacturer. In general, it is advisable to find products that meets the requirements of the GOST, and not done on that. In this case, there is hope that the cable or the wire will serve for a long time and without problems. Today it is not easy to do, but if you breed or, the quality is very important. Therefore, it is probably to search.

How to determine the cross section of the stranded wire

Sometimes conductors are used stranded - consisting of many identical thin wires. How to calculate the cross section of the wire in diameter in this case? Yes, just too. Perform measurements / calculations for one wire, consider their number in the beam, then multiply on this number. Here you will learn the cross-sectional area of \u200b\u200bthe stranded wire.

When designing a scheme of any electrical installation And the installation, the choice of cross-section of wires and cables is a mandatory step. In order to correctly select the power wire of the desired section, it is necessary to take into account the maximum consumption value.

Wiring sections is measured in square milieters or "squares". Each "square" of the aluminum wire is capable of skipping through itself for a long time heating to permissible limits to the maximum - only 4 amps, and the copper wire is 10 ampel current. Accordingly, if a power consumers consumes the power equal to 4 kilowatts (4000 watts), then at a voltage of 220 volts, the current will be 4000/220 \u003d 18.18 amps and enough to bring electricity to it copper wire section 18.18 / 10 \u003d 1.818 square. True, in this case, the wire will work at the limit of its capabilities, so we should take a margin in the section in the amount of at least 15%. We obtain 2,091 squares. And now we will pick up the nearest wire of the standard cross section. Those. To this consumer, we must conduct the wiring with a copper wire cross section of 2 square millimeters called current load. Current values \u200b\u200bare easy to determine, knowing the passport power of consumers by the formula: I \u003d p / 220. Aluminum wire will be 2.5 times thicker, respectively.

At the rate of sufficient mechanical strength, the open power wiring is usually performed by a wire with a cross section of at least 4 kV. mm. If required with greater accuracy to know a long time permissible current load for copper wires and cables, then you can use the tables.

Copper veins of wires and cables
	Voltage, 220 V		Voltage, 380 V
	talk, A.	power, kWt	talk, A.	power, kWt
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,4	50	33,0
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66,0	260	171,6

Aluminum veins of wires and cables
Section of conductive veins, mm.	Voltage, 220 V		Voltage, 380 V
	talk, A.	power, kWt	talk, A.	power, kWt
2,5	20	4,4	19	12,5
4	28	6,1	23	15,1
6	36	7,9	30	19,8
10	50	11,0	39	25,7
16	60	13,2	55	36,3
25	85	18,7	70	46,2
35	100	22,0	85	56,1
50	135	29,7	110	72,6
70	165	36,3	140	92,4
95	200	44,0	170	112,2
120	230	50,6	200	132,0

Permissible long-term current for wires and cords with rubber and polyvinyl chloride insulation with copper conductors for example
Section of conductive veins, mm.	Open
		Two single-cores	Three single-cores	Four single-cores	One two-tier	One triple
0,5	11	-	-	-	-	-
0,75	15	-	-	-	-	-
1	17	16	15	14	15	14
1,2	20	18	16	15	16	14,5
1,5	23	19	17	16	18	15
2	26	24	22	20	23	19
2,5	30	27	25	25	25	21
3	34	32	28	26	28	24
4	41	38	35	30	32	27
5	46	42	39	34	37	31
6	50	46	42	40	40	34
8	62	54	51	46	48	43
10	80	70	60	50	55	50
16	100	85	80	75	80	70
25	140	115	100	90	100	85
35	170	135	125	115	125	100
50	215	185	170	150	160	135
70	270	225	210	185	195	175
95	330	275	255	225	245	215
120	385	315	290	260	295	250
150	440	360	330	-	-	-
185	510	-	-	-	-	-
240	605	-	-	-	-	-
300	695	-	-	-	-	-
400	830	-	-	-	-	-

Permissible long-term current for wires and cords with rubber and polyvinyl chloride insulation with aluminum veins
Section of conductive veins, mm.	Open	Current, and, for wires laid in one pipe
		Two single-cores	Three single-cores	Four single-cores	One two-tier	One triple
2	21	19	18	15	17	14
2,5	24	20	19	19	19	16
3	27	24	22	21	22	18
4	32	28	28	23	25	21
5	36	32	30	27	28	24
6	39	36	32	30	31	26
8	46	43	40	37	38	32
10	60	50	47	39	42	38
16	75	60	60	55	60	55
25	105	85	80	70	75	65
35	130	100	95	85	95	75
50	165	140	130	120	125	105
70	210	175	165	140	150	135
95	255	215	200	175	190	165
120	295	245	220	200	230	190
150	340	275	255	-	-	-
185	390	-	-	-	-	-
240	465	-	-	-	-	-
300	535	-	-	-	-	-
400	645	-	-	-	-	-

Permissible long-term current for wires with copper veins with rubber insulation in metal protective sheaths and cables with copper veins with rubber insulation in lead, polyvinyl chloride, NIRITE or Rubber shell, armored and unsone
Section of conductive veins, mm.	Current *, and, for wires and cables
	single villains		two zeal			three-core
	when laying
	in the air	in the air		in the ground	in the air		in the ground
1,5	23	19		33	19		27
2,5	30	27		44	25		38
4	41	38		55	35		49
6	50	50		70	42		60
10	80	70		105	55		90
16	100	90		135	75		115
25	140	115		175	95		150
35	170	140		210	120		180
50	215	175		265	145		225
70	270	215		320	180		275
95	325	260		385	220		330
120	385	300		445	260		385
150	440	350		505	305		435
185	510	405		570	350		500
240	605	-		-	-		-

* Currents relate to cables and wires with zero living and without it.

Permissible long-term current for cables with aluminum veins with rubber or plastic insulation in lead, polyvinyl chloride and rubber shells, armored and unarmented
Section of conductive veins, mm.	Current, and, for wires and cables
	single villains		two zeal			three-core
	when laying
	in the air	in the air		in the ground	in the air		in the ground
2,5	23	21		34	19		29
4	31	29		42	27		38
6	38	38		55	32		46
10	60	55		80	42		70
16	75	70		105	60		90
25	105	90		135	75		115
35	130	105		160	90		140
50	165	135		205	110		175
70	210	165		245	140		210
95	250	200		295	170		255
120	295	230		340	200		295
150	340	270		390	235		335
185	390	310		440	270		385
240	465	-		-	-		-

Permissible long-term currents for four-core cables with plastic insulation to voltage up to 1 kV can be selected according to this table as for three-core cables, but with a 0.92 coefficient.

Summary of wire sections, current, power and load characteristics
The cross section of copper lived wires and cables, sq.mm	Permissible long load current for wires and cables, and	Rated current automatic protection, and	Limit of the current automatic protection, and	Maximum power of single-phase load at U \u003d 220 B	Characteristics of approximate single-phase household load
1,5	19	10	16	4,1	lighting and alarm group
2,5	27	16	20	5,9	outlet groups and electric floors
4	38	25	32	8,3	water heaters and air conditioning
6	46	32	40	10,1	electric stoves and brass cabinets
10	70	50	63	15,4	introduction supply lines

The table shows the data based on PUE, to select sections of cable-conduction products, as well as the nominal and maximum possible currents of protection machines, for single-phase household loads most often used in everyday life.

We hope this information was useful for you. We remind you that you can buy excellent quality at a low price.

Often, before purchasing cable products, it is necessary to independently measure its section to avoid deception by manufacturers, which due to savings and establishing a competitive price can slightly underestimate this parameter.

Also know how the cable cross section is determined, it is necessary, for example, when adding a new power consuming point in rooms with an old electrical wiring, which does not have any technical information. Accordingly, the question of how to find out the cross section of the conductors remains relevant.

General information about cable and wire

When working with conductors, it is necessary to understand their designation. There are wires and cables that differ from each other internal device and technical characteristics. However, many people often confuse these concepts.

The wire is a conductor having one wire or a group of wires woven with each other, and a thin common insulating layer. The cable is called lived or a group of cores having both its own isolation and a common insulating layer (shell).

Each of the types of conductors will correspond to their methods for determining sections that are almost similar.

Materials conductors

The amount of energy that the conductor transmits depends on a number of factors, the main of which is the conductive vein material. The material of the veins and cables can be the following non-ferrous metals:

1. Aluminum. Cheap and lightweight conductors, which is their advantage. They are inherent in such negative qualities as low electrical conductivity, tendency to mechanical damage, high transition electrical resistance of oxidized surfaces;
2. Copper. The most popular conductors who have, compared to other options, high cost. However, they are inherent in small electrical and transient resistance on contacts, sufficiently high elasticity and durability, lightness in spike and welding;
3. Alummate. Cable products with aluminum veins that are covered with copper. They are characterized by a little less electrical conductivity than the copper analogs. They are also inherent ease, mean resistance with relative cheapness.

Important! Some ways to determine the cross-section of cables and wires will depend on the material of their vein component, which directly affects the throughput power and current strength (the method of determining the section lived in power and current).

Measurement of the cross section of conductors in diameter

There are several ways to determine the cross section of the cable or wire. The difference in determining the cross-sectional area of \u200b\u200bwires and cables will be that in cable products it is required to perform measurements of each core separately and summarize the indicators.

For information. Measuring the parameter in question by testing and measuring instruments, it is necessary to initially measure the diameters of the conductive elements, it is desirable to remove the insulating layer.

Devices and measurement process

Measures for measurements can perform a caliper or micrometer. Usually mechanical devices are used, but electronic analogs with a digital screen can also be applied.

Basically, the diameter of the wires and cables is measured by means of a calipers, as it will be found in almost every household. It is also possible to measure the diameter of the wires in the working network, such as a socket or shield device.

Determination of the cross section of the wire diameter is performed according to the following formula:

S \u003d (3.14 / 4) * d2, where D is the diameter of the wire.

If the cable in its composition has more than one core, then it is necessary to measure the diameter measurements and the calculation of the section according to the above formula for each of them, after combining the result, using the formula:

Singch \u003d S1 + S2 + ... + SN, where:

• Singchp - the total cross-sectional area;
• S1, S2, ..., Sn - cross sections of each vein.

On a note. For the accuracy of the result obtained, it is recommended to measure at least three times, turning the conductor in different directions. The result will be the average.

In the absence of a caliper or micrometer, the conductor diameter can be determined by the usual line. To do this, you need to perform the following manipulations:

1. Clear the insulating layer of the veins;
2. Having tightly to each other's turns around a pencil (there must be at least 15-17 pcs.);
3. To measure the winding length;
4. Split the amount obtained on the number of turns.

Important! If the coils are not laid on a pencil evenly with gaps, the accuracy of the results of the measurement of the cable cross section of the diameter will be in doubt. To increase the accuracy of measurements, it is recommended to be measured from different sides. Thick cores to put on a simple pencil will be difficult, so it is better to resort to the caliper.

After measuring the diameter, the cross-sectional area of \u200b\u200bthe wire is calculated by the formula described above or is determined by a special table, where each diameter corresponds to the size of the cross section.

The diameter of the wire that has in its composition ultra-thin veins, it is better to measure the micrometer, as the caliper can easily break it.

Determine the cable cross section in the diameter is easiest through the table, which is shown below.

Correspondence table wire diameter cross section

Diameter of the conductor element, mm	Spectacle area of \u200b\u200bthe conductor element, mm2
0,8	0,5
0,9	0,63
1	0,75
1,1	0,95
1,2	1,13
1,3	1,33
1,4	1,53
1,5	1,77
1,6	2
1,8	2,54
2	3,14
2,2	3,8
2,3	4,15
2,5	4,91
2,6	5,31
2,8	6,15
3	7,06
3,2	7,99
3,4	9,02
3,6	10,11
4	12,48
4,5	15,79

Segment cable cross section

Cable products with a cross section of up to 10 mm2 are almost always rumbled. Such conductors are quite enough to provide household needs of houses and apartments. However, with a larger cross section of cable inputs from external electrical network Can be performed in the segment (sector) form, and determine the cross section of the wire in diameter will be quite difficult.

In such cases, it is necessary to resort to the table where the size (height, width) of the cable takes the corresponding value of the cross section. Initially, it is necessary to measure the height and width of the desired segment to measure the height and width of the desired segment, after which the required parameter can be calculated by the relationship with the data obtained.

Table of Calculation of the Sector of the Electrocabyl Accommodation

Type of cable	Segment segment area, mm2
	S.	35	50	70	95	120	150	185	240
Four-core segment	at	-	7	8,2	9,6	10,8	12	13,2	-
	sh	-	10	12	14,1	16	18	18	-
Three-core segment multi-breeding, 6 (10)	at	6	7	9	10	11	12	13,2	15,2
	sh	10	12	14	16	18	20	22	25
Three-core segment one-robust, 6 (10)	at	5,5	6,4	7,6	9	10,1	11,3	12,5	14,4
	sh	9,2	10,5	12,5	15	16,6	18,4	20,7	23,8

The dependence of current, power and sections lived

Measure and make calculations of the cable cross section of the cable diameter is not enough. Before laying wiring or other types of power grids, it is also necessary to know the bandwidth of cable products.

Choosing a cable, you must be guided by several criteria:

• the power of the electric flow, which will pass the cable;
• power consumed by sources of power consumption;

Power

The most important parameter for electrical work (in particular cable laying) is throughput. The maximum power transmitted over it depends on the conductor cross section. Therefore, it is extremely important to know the overall power of energy consumption sources that will be connected to the wire.

Usually manufacturers household appliances, devices and other electrical products indicate the label and the maximum and average power of consumption attached to them. For example, a laundry washing machine can consume electricity in the range of tens of W / h with rinse mode to 2.7 kW / h when water is heated. Accordingly, the wire with the cross section must be connected to it, which is enough to transmit the electricity of maximum power. If two or more consumers connect to the cable, then the total capacity is determined by the addition of the limit values \u200b\u200bof each of them.

The averaged power of all electrical appliances and lighting devices in the apartment rarely exceeds 7500 W for a single-phase network. Accordingly, the cross-section of cables in the wiring must be selected for this value.

So, for the value of a total power of 7.5 kW, it is necessary to use a copper cable with a cross section of 4 mm2 veins, which is capable of skipping about 8.3 kW. The conductor cross section with aluminum residential in this case should be at least 6 mm2, passing the power of the current from 7.9 kW.

In individual residential buildings, a three-phase power supply system is often used at 380 V. However, most of the equipment is not designed for such an electrical barrier. 220 V voltage is created by connecting them to the network through zero cable with uniform distribution Tower load on all phases.

Electrotok

Often the power of electrical equipment and technology may not be known to the owner due to the lack of this characteristic in the documentation or completely lost documents, labels. The output in such a situation is one - make calculation by the formula yourself.

Power is determined by the formula:

P \u003d U * i, where:

• P - power measured in watts (W);
• I is the power of the electric flow, measured in amperes (A);
• U is an applied electrical barrier measured in volts (B).

When the power of the electric flow is unknown, it can be measured with instrumentation: an ammeter, a multimeter, current-measuring ticks.

After determining the power consumed and the power of the electric flow, it is possible to find out the required cross section of the cable using the table below.

Calculation of the secting of cable goods for current load must be made to further protect them from overheating. When the conductor passes too much electrothes for their cross section, then the destruction and melting of the insulating layer can occur.

The maximum allowable long-term current load is the quantitative value of the electrotock, which can skip the cable for a long time without overheating. To determine this indicator, initially it is necessary to sum up the power of all energy consumers. After that, to calculate the load by formulas:

1. I \u003d Pς * KI / U (single-phase network),
2. I \u003d pς * ki / (√3 * u) (three-phase network), where:

• Pς - the total power of energy consumers;
• Ki is a coefficient equal to 0.75;
• U is an electrical barrier on the network.

TAblitz matching the area of \u200b\u200bthe cross section of copper livedconductive products current and power *

Cable-conductor section	Electric slip 220 B.		Electric slip 380 B.
	Current strength, and	power, kWt	Current strength, and	power, kWt
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	50	11	40	26,4
10	70	15,4	50	33
16	90	19,8	75	49,5
25	115	25,3	90	59,4
35	140	30,8	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66	260	171,6

*Important! Explorer with aluminum cores correspond to other values.

Determination of the cable product in cross section is a particularly important process in which the miscalculations are unacceptable. All factors, parameters and rules are required to be taken into account, trusting only to their calculations. The measurements must coincide with the tables described above - in the absence of specific values \u200b\u200bin them, they can be found in the tables of many reference books of electrical engineering.

Video

When buying or always, it is worth paying attention to its actual cross section, since it is often in stores in stores you can find cable products with a cross section that does not correspond to its marking, and significantly. And this, as you understand, can lead to overheating of the cable and as a result of a short circuit.

To independently calculate the actual cross section, we will help us a few simple ways. The most convenient way is to calculate the cross section of the wire in its diameter. To do this, you will need a micrometer or caliper.

Measuring the core diameter, I remember the formula of the area of \u200b\u200bthe circle:

For example, take the wire, on the insulation of which the labeling WGG 3 × 2.5 is indicated. We measure the cord diameter of the vein - we get 1.7 mm. Next, we substitute this value in the formula:

SKR \u003d 0.785 x 1.7 x 1.7 \u003d 2.27mm2.

It turns out that the actual cross section of the wire is 2.27mm2 instead of the declared 2.5.

With a single-core wire, everything is clear, but what about multi-core?

Here everything is about as well. We take one vein from the stranded wire and measure the caliper. For example, the diameter turned out to be 0.4 mm.

SKR \u003d 0.785 x 0.4 x 0.4 \u003d 0.125mm2.

Then we count the total number of veins in the wire, suppose 12.

And now we know the general cross section of the wire multiplying the value of one vein 0.125mm2 to the amount of lived - 12.

S \u003d 0.125 x 12 \u003d 1.5mm2 - This is the actual cross section of the wire.

Of course, not everyone has a caliper and the more micrometer, in this case they will have to go in a different way.

To do this, we need a ruler and pencil, or some round rod. Remove isolation from the wires and wake up for about 10 turns on the rod. The main thing is that the turns are tightly fit to each other, without gaps.

The line measure the length of the winding and divide on the number of turns. We obtain the diameter of the vein. And then on the same formula we find the cross section of the vein. The method is quite accurate, but not very convenient - and in the store in this way do not measure and thick veins are not wounded.

In order to do not extend the cross section on the calculator each time, lower the table of the correspondence of diameters and sections of the wires in which there are the most common sizes. You can rewrite it or print and take with you to the store. It will only be necessary to measure the diameter of the core and compare with the value from the table. If the measured value is significantly different from the table, then such a cable is better not to buy.

You need to determine what section of the wire is just half an end. You need to find the desired cross section. The fact is that some manufacturers for increasing profits produce cables with a lot of smaller cables than stated in the accompanying documents. For example, there are stated veins of 4 mm 2, and in real life - 3.6 mm 2 or even less. This is a decent difference. If you do not notice it, the wiring can warm and this, in turn, can lead to a fire. Therefore, we will talk further about how to find out the cross section of the wire in diameter, because the diameter can always be measured. Further, according to the measurement results, we learn the actual settings of the vein.

At the time of buying electric cable Or wires to check the cross section of the core, it is necessary to measure its diameter. There are several ways for this. You can use measuring instruments such as caliper or micrometer. They measure the size of the bare part of the conductor. The device is simply attached to the dwelling, clamping between sponges, and the result is displayed on the scale.

How to measure the diameter of the veins - take a caliper or micrometer

For private use of measurement, quite accurate, with a small error. Especially if electronic devices.

For the second method, only a ruler and some smooth rod are needed. But in this case it will still have to make calculations, however, very simple. About this method - further.

Rule + rod.

If there is no measuring instruments in the farm, you can do the usual line and any rod of the same diameter. This method has a high error, but if trying to be quite accurate.

We take a piece of wire with a length of about 10-20 cm, removing isolation. Having coated copper or aluminum wire to the rod of the same diameter (any screwdriver, pencil, handle, etc.). The coils are laid neatly, close one to another. Number of turns - 5-10-15. We consider the number of full turns, take a ruler and measure the distance that the wrapped wire occupies on the rod. Then divide this distance to the number of turns. As a result, we obtain the diameter of the conductor.

As you can see, there is an error. First, you can easily put the wire. Secondly, there is no accurate measurement. But if you do everything carefully, the differences with real dimensions will be not so big.

How to measure the diameter of the stranded wire

If you need to know the diameter of the stranded wire, measurements are carried out with one of the wires, its components. The process is the same: to remove the insulation, remove the braid (if there is), flush the wire, highlighting one, carry out measurements in any way (micrometer or wound on the rod).

Found size Multiply to the number of wires in one conductor (flush and count). That's all, the diameter of the stranded conductor you found. It remains to learn how to find out the cross section of the wire in diameter, because when planning the wiring it is used precisely the cross-sectional area.

How to calculate according to the formula

Since the cross section of the wire is a circle, we will use the formula of the area of \u200b\u200bthe circle (in the photo). As we see, it is possible to calculate the cross section of the wire using the measured diameter or calculate the radius (divide the diameter by 2). For clarity, we give an example. Let the measured wire size of 3.8 mm. We substitute this figure in the formula and get: 3,14 / 4 * 3.8 2 \u003d 11.3354 mm 2. It can be rounded the result - it will be 11.3 mm 2. An impressive cable.

The second part of the formula uses radius. It is half the diameter. That is, to find a radius, diameter divide by 2, we get 3.8 / 2 \u003d 1.9 mm 2. Next, we substitute in the formula and we obtain: 3,14 * 1.9 2 \u003d 11.3354 mm 2.

The numbers coincide that it should be. So, with the diameter of the wire is 3.8 mm, the area of \u200b\u200bits cross section is 11.34 mm 2. You know how to find out the cross section of the wire according to the formula. But it is not always possible to deal with counting. In this case, the table can help.

Determining the cross section of the wire diameter on the tables

For cable-conductive products there is a specific set of sections that are written in standards. Knowing what section you need, we find the diameter of the conductor on the table. Then you only need to find products with the necessary parameters.

Conductor section	Diameter
0.5 mm2	0.8 mm
0.75 mm2	0.98 mm
1.0 mm2	1,13 mm
1.5 mm2	1.38 mm
2.0 mm2.	1.6 mm
2.5 mm2	1.78 mm
4.0 mm2.	2.26 mm
6.0 mm2	2.76 mm
10.0 mm 2.	3.57 mm

Now a little about how to work with this table. You go beyond the products with certain parameters. For example, you know that you need a cable with a cross section of 4 mm 2. Having found on the table the corresponding value, we are looking for the required parameters in cable products. In this case, it will be necessary to find wires with a diameter of 2.26 mm. If in the store or in the market we find close parameters - it is already good. It happens that the parameters specified on the tag are overestimated, i.e. Real cross section of conductors less.

There are two ways to find the desired one. The first is to look for products that correspond to the declared parameters. Perhaps spending some time, you will be able to find. But a lot of time will go to search. It was too little responsible manufacturers. There is, by the way a sign that can be focused. This is the price. It is significantly higher than the average. This is because a greater amount of copper or aluminum is spent. If you use this sign, there will be less time.

The second option is to see products with the stated big denomination. In our case, we argue like this: we need a wire in 4 squares. The next software is 6 mm 2. It is very likely that the parameters of this cable in real life will be close to the required 4 squares. Perhaps the cross section of the conductors will be more, but it is good - the wiring will definitely won't bask. The minus of this option is that you will spend more money, as such cables are more.

In general, you know not only how to find out the cross section of the wire in diameter, but also how to choose the desired one. Even if the stated characteristics do not coincide with real.