wiring in an apartment or private home can be compared with the water system through which can pass only a certain amount of water. Similar can be said about cable - it is designed for a well-defined maximum consumption appliances power. This means that the selection of conductor cross-section should be approached very carefully.
At the desired diameter can be influenced by many factors. The main thing - it's total consumption appliances power (W or kW). If it is exceeded, the wire starts to warm up. But the most dangerous thing that this process begins to increase exponentially. In other words, the conductor is heated under overload. As a result, its resistance increases, which leads to further heating. Outcome sad - inflammation of isolation and short-circuiting. Conclusion - correct calculation of section - the key to long term home electrical service. And so as not to clog the head unnecessary formulas can perform all of the calculations by the online calculator.
Diameter cable (Cross-section) is determined in mm2. wire marking necessarily contains this data. For example, on a product marked "CG 3h1.9". It means "copper flexible cable with three conductors, cross-section 1.9 mm2.
The diameter of the wire It can be calculated by the formula I = P /U ·cosφWhere:
- I - current;
- P - total power of the consumers;
- U - stress at household single phase - 220 volts;
- cosφ - constant coefficient (usually it does not take into account for domestic networks).
resistance calculation as follows - R = p · L / SWhere:
- p -resistivity;
- R - metal resistance;
- S - section of the wire;
- L - length of the conductor.
Counting conductor diameter of the power consumption should take into account number of phases. For a voltage of 220 and 380 in a different formula. When filling out the online calculator respective fields, this figure accounted for.
Basic data required for the calculation:
- The length of the conductor - is measured on the line defined by electrical induction machine;
- cable material - copper or aluminum (which have a different resistance);
- load power - it is necessary to lay down the power consumption of devices;
- The number of phases and the mains voltage - for the apartments - 220, in private homes possible 380.
Only properly calculating the necessary parameters can be confident in the quality of installation and home electrical reliability. But the data obtained as a result can not be considered as final. Experienced electricians suggest adding 15-20% to a calculated parameters for the modernization possibilities. In our electronic age is not known, it does not have to whether or not the network is paved additional appliances. So that safety does not hurt.