How to calculate the wire cross section?
The question of how to calculate the cross-section of a wire is relevantand for those who plan repairs in the apartment or those who want to conduct work on the electrification of the cottage. There are two ways in which you can achieve an acceptable result: the traditional method "by eye" used by most electricians or based on the knowledge of the basics of electrical engineering.
Why do we need such calculations if there arespecial tables, in which the manufacturer enters information about their products? The fact is that each company considers the value of the current in its own way: somewhere it is only 120% excess, and somewhere even 200%. Of course, there can be no question of long work with a double overload, since the heated conductor will melt the insulation and at best operate an automatic shutdown.
Calculation of the wire cross section: instruction
For an accurate calculation, you need to know from whichmaterial is made wire. If it is copper, the current density in it will be from 6 to 10 amperes with a cross-sectional area of 1 square millimeter; if aluminum, which occurs infrequently, then this parameter does not exceed 4-6 units.
Such a wide spread is caused by a stock of material: 6 amperes are conditions of normal operation, and excess to 10 is already an overload that is permissible for a short time.
It turns out that a wire whose areais 1 square millimeter in cross section, can withstand current up to 10A, 2 millimeters to 20A, etc. Knowing the voltage in the network, the average value of which reaches 220V, we obtain an output power of 4.5 kW for a 2 mm conductor.
How to calculate the cross-section of a wire according to the traditionalmethod? Here it's still simpler: you need to remember that copper wires with an area of 1.5 square meters. mm used to connect the lighting, and 2.5 square meters. mm already go to the wiring of the network in the apartment.
Here you can immediately take into account the appliedload. If the main consumer is a computer, then 600 W / 220V is 2.7A, i.e. in the reserve there is still about 17A, but this does not mean that it is worth testing the network by simultaneous connections of TV irons, etc. Even if the wiring carries such an attitude, it may not like the Chinese extension cord, as a result of which everything will also short circuit.
Another point worth drawing onattention - the use of copper-based alloys by producers. Such materials have a lower value of the permissible current density, so you should not save on wiring.