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August 12, 2017 18:06

The correct calculation of the cable cross section of the load - and the principle of the table

calculation - section cable How is the cable cross-section calculation load must know every self-respecting man.And this knowledge is necessary for practical, everyday purposes.You have to understand that in the Soviet period, the calculation load on the wiring of residential buildings was made, implying average family that will be living in an apartment.However, while there was no such diversity (and this amount) of various household appliances, which is now available in almost every home.

growth of individual building also attaches to such issues more and more people.Indeed, any new and involves laying of cables and wire insulation power.Now on the Internet at some sites even have special calculators to determine the cross-section.Like, why to know the calculation?

The answer is simple - no one will deny that everything must be done intelligently.For example, what if the hand is not a cable with wires of cross-section that is "counted" computer?In the shop - then spend time and money, especially if there is some reserve, as it should be a good host.Knowing how, on the basis of which the calculations are made, clearly understanding their essence, you can always find a replacement for the missing material, consider the prospect.And if you make a lining "about", from which it is, then it is likely a short circuit or wires (and fire), or banal breakage of the line, which still have to search.


All calculated wire "current."The implication, which forces the current (in Amps) is able to withstand the wire over any time you want, of course, without any damage.If there is a connection at home, it is all done on the project.And if you want to "power up" a separate room, for example, an extension?In this case, you need to think about what the room will be consumers.It is thought all: light bulbs in chandeliers, wall lamps and other lighting equipment, televisions, refrigerators.

All data on the consumption of each unit of power can be found in his passport.Many such devices have data and special nameplates (plates), which are bolted (glued), usually from the rear side.Thus all possible counts of consumed power in the room.Something like in "All Inclusive" regime.

calculation - section click for larger


calculation must take into account that the wire sizes are calculated according to the tables that match the type of the applied voltage.For the vast majority of residential buildings is the single-phase voltage.Therefore, the table needs to look for him, but not for 3-phase.There are other values.So, to see the cross section, we need to determine which current need to focus.Although tables provide data on the current or power, or the total power.There is a summary table.But the formula for single-phase circuit 220 is useful to remember.

P = J x U x cos / KH

  • P - total power of all "consumers" e / energy;
  • J - the required amperage for the calculation of the table;
  • U - voltage network.It is equal to 220;
  • COS - for household appliances is accepted equal to "1";
  • Ki - coefficient taken equal to 0.75.

By substituting known values ​​(as in school), we obtain:

P = J x 220 x 1 / 0.75 or J = 0,75 P / 220

Learning current value, find the section along the tableone core.However, we must bear in mind that it is always necessary to make the stock "strength", just in case.Therefore, current value found should be increased by a third, and then on the table to look for the desired section.If this wire is not at hand, you can use a larger wire gauge.But smaller - no.


wire When selecting wire should give preference to copper.He is stronger than aluminum, less oxidized, is more resistant to bending.At the same current strength of the cross section of the copper wire is less.Hence, the wiring will be more "compact".