Before proceeding with the design of electricians in your house, apartment, cottage, you must first draw up a calculation scheme that will show all the expected loads in the rooms, as well as the length of individual sections of the cable. To compile such a map, you will need to calculate the electrical load. Correctly drawn up electrical diagram of the facility will allow you to choose the wires and cables of the required sections. In cases where the cable cross section is less than that required for the normal functionality of large power units, the cable begins to overheat. And as a result, the destruction of insulation occurs. As a result, the duration of operation and the level of reliability of wiring is significantly reduced. Moreover, overheating of the cable can cause fire. Similar situations happen all the time when residents (for the sake of economy) use a wire section smaller than necessary. The result is short circuits and fires. Let's see what constitutes an electrical load calculation.
The correct choice of switching devices, as well as the cross-section of the cable, largely depends on various values ββof the parameters of the electrical networks. The most important of them is the electric load current . At the design stage, the indicated value can be determined solely by the mathematical method. It is considered very important to calculate the electrical load in three-phase networks, since the load in them must be placed evenly among the phases in order to avoid voltage distortions. However, in household networks, such a calculation must be carried out when designing not only switchboard, but also residential premises.
The calculation of the electrical load is carried out at known values ββof the power of electrical devices, the nature of the loads, as well as the mains voltage. For single-phase networks, the formula for determining the load current is used: I = P / (U Γ cosΟ), where:
- U is the value of the actual network voltage (measured in volts);
- cosΟ is the corresponding power factor.
For three-phase networks, the calculation of electrical loads is carried out according to the following formula: I = P / (1.73 Γ U Γ cosΟ).
Depending on the nature of the load, a power factor value is selected. When calculating the reactive load of high power (chokes of lighting devices, electric motors, welding transformers, etc.), the average value cosΟ = 0.8 was adopted. When determining the power current for active loads (heating elements, incandescent lamps), the power factor is approximately equal to unity. However, a reactive component is always present in any active load; therefore, it is customary to use cosΟ = 0.95 for calculations.
In conclusion, we recall that electricity does not forgive mistakes, it will not give a second chance. Safety, as well as the reliability of electrical systems - that's what any professional electrician wants. And it doesnβt matter where he works: in production or in the private sector. Electrical load is one of the most important design parameters that must be considered in any system.