How to make a choice section of the cable?

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Our days can justifiably be called the era of repair: building new homes, and the vast majority of existing buildings actively repaired.This is especially true for private sector buildings, constructed in the range from 50 to 80s.Used at the time materials are partially lost their properties due to the natural aging process, possible changes of the soil led to a grid of cracks on the walls and so forth. In addition, the changed design approaches and, importantly, are higher requirements to the functional structure.For example, if before the choice of cable cross-section of the load when performing household wiring was made on the basis of the total consumption of no more than 1-1.5 kilowatts, but now these values ​​increased significantly.Who are the appropriate minimum 3 kilowatts (current 16 amps).Thus, both in private homes and apartments must be in accordance with the new requirements, make selections Wire and change the whole wiring.We are not in vain in the early repair touched on: the fact that the majority of replacement methods are destructive for interior decoration.To lay new cable, most often in the walls do Grooves.Of course, you can use the plinth with cable channel and plastic boxes, but this solution is not fit to every interior.

How satisfied choice of cable cross-section?Let's say right away: this is no big deal.The task handle even the students.We need to sit down with a pen and a sheet of paper, make a list of the most powerful energy consumers and to analyze which of them will be lit simultaneously.Let's look at a simple example, how to make a variety of cable sizes.

task - to connect the power washing machine.Sizing of cable begins by examining the passport data of the device - must find the power consumption.Since in relation to machines manufacturers a bit tricky, you need to carefully approach the issue.It reads: "Power - 200 W".However, below for a designation on the characteristics of the heating element.For it is stated for 2 kW.Thus, the amount of machine consumes 2.2 kW.It is important to take into account such "trifles", or incorrectly selected Cable simply burn out.It is necessary to perform a variety of cable sizes for power.

between the current and the power value has a direct relationship.The formula is:

P = U * I,

where P - is power;U - voltage;I - current.

in home electrical first factor constant at 220 volts.

know the value of the machine power (2.2 kW), it is necessary for the above formula to calculate the current:

I = 2200 W / 220 V = 10 amperes

Then you should use reference tables, which provide a suitable material cable conductor, its section, method of laying (open in the pipe wall) and the current value.Tables are provided in the book "Rules for Electrical Installation."They can also be found in the global network - this information is publicly available.In this case, if the "take" of copper wires, their section must be at least 0.75 square (15 Amp current for open wiring).Of course, 30% of the stock is excessive, but because the wire is usually not placed open, the current allowed will be smaller.Furthermore, the near minimal cross section (0.5) set for 11 amps, which is insufficient.

When selecting a home wiring uses the same principle.The difference is that you must take into account the sum of the power of devices that can be simultaneously switched to any branch.