Increasing the thickness of a conductor by 6 calibers practically corresponds to doubling the thickness (the sixth power of 1.1229322 is 2.005…). It is also clear that decreasing the thickness by three calibers halves the cross-sectional area.
Multi-core conductors
With multi-core conductors, things are not so simple. -core cables as for single-core ones, this is actually incorrect, since in a multi-core conductor, the total cross-sectional area must be fusion data through the cross-sectional areas of small strands, and the equivalent diameter through the diameter of individual strands laid according to the principle of dense packing. For example, for a 7-core cable, the conductor diameter is geometrically equal to three diameters of the strands, for a 19-core cable – 5 diameters, and for intermiate ratios, the diameter is calculat through an intermiate coefficient.
It is clear that the integer value of the coefficient (and always odd) will only be with a strictly defin number of wires in the conductor. For a 7-wire, this coefficient is 3, for a 19-wire – 5, for 37 – 7, for 61 – 9. It is not difficult to calculate such “correct” configurations:
But in real life, for very_multi_core_conductors, “incorrect” numbers of cores are us, and then the actual core diameter has to be determin empirically.
In the table below, the diameter of a single core is calculat how to prepare a website for promotion in yandex the same formula as for single-core conductors, then the cross-section of the core is calculat, then the total cross-section of all cores in the conductor, and then the calculat diameter is given for the “correct” configurations. The rightmost column is the actual diameter, which is also call “ruc” in some sources. As you can see, the difference between the theoretical and actual diameters is not that great.
We hope these tables contain all the values you ne :).
Example of calculating cable cross-section.
Cable products are now present on the market in a wide range, the cross-section of the cores is from 0.35 mm.sq. and higher, this article will provide an example of calculating the cable cross-section.
To calculate the resistance of a conductor, you can use the italy numbers resistance calculator.
Incorrect selection of cable cross-section for household wiring can lead to the following results:
1. A linear meter of an excessively thick core will cost more, which will cause a significant “blow” to the budget.
2. The wires will soon start to heat up and melt the insulation if the wrong conductor diameter is chosen (smaller than necessary) and this can soon lead to a short circuit or spontaneous combustion of the electrical wiring.
In order not to waste money, before starting to install electrical wiring in an apartment or house, it is necessary to correctly calculate the cable cross-section depending on the current strength, power and length of the line.
Calculation of cable cross-section bas on the power of electrical appliances.
Each cable has a nominal power that it can withstand when electrical appliances are operating. When the power of all electrical appliances in the apartment exces the rat value of the conductor, an accident will soon be unavoidable.
You can calculate the power of electrical appliances in an apartment or house yourself. To do this, you ne to write down the characteristics of each device separately on a piece of paper (TV, vacuum cleaner, stove, lamps). Then all the obtain values are summ up, and the finish number is us to select the optimal diameter.
It is worth paying attention to the fact that the resulting number must be multipli by the correction factor – 0.8. This factor indicates that only 80% of all electrical appliances will work at the same time. Such a calculation will be more logical, because a vacuum cleaner or a hair dryer will definitely not be in use for a long time without a break.
An example of calculating the cable cross-section by power is given in the tables:
As can be seen from the tables, each specific type of cable has its own data values; you only ne to find the closest power value and look at the corresponding cross-section of the wires.
As an example, the calculation of the cable cross-section by power looks like this:
Let’s assume that the total power of all devices in the apartment is 13 kW. It is necessary to multiply the obtain value by a coefficient of 0.8, as a result this will give 10.4 kW of actual load. Then the appropriate value must be found in the table column. The closest figure is 10.1 for a single-phase network (220V voltage) and for a three-phase network the figure is 10.5. This means that we stop choosing the cross-section for a single-phase network on a 6-millimeter conductor or for a three-phase network on a 1.5-millimeter conductor.
