How to calculate the wire cross-section for the input power cable
In order to calculate this figure, you need to subtract the total power of all electrical appliances( kettle, washing machine, iron, ovens, heaters, lighting devices) that can be used in the future. The power of electrical appliances can be learned by examining labels, passports, boxes and the products themselves. The resulting indicator is multiplied by a factor of 1.5, or 2, to create a stock.
For convenience, the room in which the wiring is calculated can be divided into zones and calculate the cross-section of wires based on this division, for example, separately for the house, the garage. This should be done as accurately as possible, since this will determine the efficiency of the tripping device's operation. If the calculation is incorrect, the machine will either not work in emergency situations, or it will be shut off unnecessarily if several powerful electrical devices are connected to the network simultaneously.
Calculation of the cross-section of the wires should be done with a reserve, and the automatic switching devices must be selected as accurately as possible, so that when an emergency occurs, it works most effectively.
How to calculate the cable section by load
After the total power factor has been calculated, you need to determine the cable type. Copper and aluminum cables can be used for these purposes. But nowadays copper is mainly used, as aluminum is more fragile and requires a larger cross-section. Therefore, their use is not advisable.
For an example, take the total power of all electrical appliances 10-15 kW.If we use a copper cable, then for this load we need a cross section of 6 kV.mm. And for aluminum - 10 square meters.mm. When the load is twice as large, the cable cross section increases threefold. These calculations are applicable for a single-phase open gasket. But if it is closed, then in order to prevent overheating and fire, it is necessary to make the calculated index more by a factor of 1.5.
How to calculate the wiring inside the house
For cable routing within the house, the following cross-sections are used:
- For sockets use a cable with a cross-section of 2.6 square meters.mm.
- For lighting devices - a cable with a minimum cross-section of 1.5 square meters.mm.
Special attention should be paid to the kitchen, since it is there that powerful appliances are used in large quantities( washing machines, electric ovens and ovens, a warm floor system).This factor needs to be taken into account and, possibly, to make separate wiring for the most powerful electrical appliances. Thus it is necessary to take into account such indicators:
- For a load of 3 kilowatts, the minimum cross-section of the cable is 1.5 square meters.mm;
- For a load of 4.5 - 2.5 square meters.mm;
- At a load of 6 kilowatts - 4 square meters.mm;
- If the load is 8 kilowatts, then the required cross-section of the cable is 6 square meters.mm.
Conclusions
You can determine the required cable section yourself, armed with a calculator and do not complex calculations, paying attention to the tables from the Rules for the operation of electrical installations. But if there is no desire or opportunity to do it yourself, then you can use the online calculator to calculate the necessary cross-section of the wire or use the services of professionals.
