How to calculate and choose the right power cable

Using the right type of cord with electrical appliances in your home not only helps you save electricity but also helps protect the equipment to use longer. In addition, it also minimizes the possibility of fire and explosion due to short circuit, open circuit ….

Signal control wire Dusonc.

Used for power supply to the inside of buildings and in addition it is used for industrial control circuits.

Here, Quan Pham would like to share how to calculate and choose the right type of electrical conductor with household appliances:

For rated electricity 220v, we can take the approximate value for easy calculation:
– For copper wire: Allowable current density Jđ = 6A/mm2, equivalent to 1.3kW/mm2.
– For aluminum wire: Allowable current density Jn = 4.5A/mm2, equivalent to 1kW/mm2

Example 1: Total power of electrical appliances used at the same time in the family P = 3kW (see power parameters on the case of electrical equipment and then add it up). If copper wire is used as the main axis in the household, each phase must have a minimum cross-section (S):
S= P/Jđ , we do the calculation: S= 3kW/1.3kW/mm2 = 2.3 mm2
So we should choose an electrical cable with a minimum cross-section of the backbone wire in the family of 2.3 mm2. On the market, there are cords of 2.5 mm2 and 4mm2 sizes (we often call them two and a half cups or four and a half cups,…). To prevent load growth, a wire size of 4 mm2 should be used.

Example 2: Household branch wire (mobile cord) from electrical outlet or the switch to lights, fans, televisions, refrigerators or other appliances with a capacity of less than 1kW, it is recommended to use a series of soft soup cables, with a cross section of 2x 1.5mm2. The mobile wires used for electric stoves, fireplaces … with capacity from 1kW to 2kW should use PVC coated cable with two layers of insulation, cross section 2x 2.5mm2, to ensure safety both electrically and physically. mechanics.
For other electrical equipment with capacity greater than 2kW, depending on the capacity, the wire cross-section should be calculated and selected as guided in Example 1.

Many short-circuit fires that cause fires in homes, hotels,… are caused by not using the correct electrical conductor cross-section compatible with the capacity of electrical equipment, increasing the load without paying attention to the wire cross-section. permission, so users need to be aware.
In addition, cockroach rats are also one of the causes of electrical short-circuits, so it is necessary to wrap electrical wires with specialized equipment.