And so you decided to repair and decided to change the wiring in the apartment from the old aluminum to a more reliable copper one. The question immediately arises before you, and what wire cross-section to choose so that the wire can withstand all the electrical equipment available in the apartment? Which in a modern apartment is quite a lot and it consumes a large amount of electricity. To begin with, you need to decide on the amount you need to comfortably connect electricity consumers, sockets.
Copper cable is considered more reliable for wiring, but it is at least twice more expensive than aluminum.
And when you figured out this issue and considered everything thoroughly, you can take on the wires and their cross-section, to which you will connect them. Copper wire is best suited for such purposes, with a solid or (in the most extreme case) a stranded core with good vinyl insulation, such as VVG. Fortunately, there is an abundant selection of such products on the market and you will not spend much time searching for it. Basically, a wire with a cross-sectional diameter of 2.5 square millimeters is suitable for connecting internal sockets, if you use sockets with grounding, then you should buy a three-core wire of the same cross-section. A smaller diameter wire is suitable for wiring room lighting - 1.5 square millimeters is quite enough.
What section and where to lay
- The wire for room lighting, from the dividing box, must be laid separately from the wire to which the sockets will be connected, since the sockets will consume more electricity and, accordingly, will heat up. Devices of higher power are connected to them.
- For stationary electrical appliances of high power, the wire must be laid with a separate and larger section. Such devices include an electric stove, a washing machine, an electric oven. The wire for them must be selected with a cross section of 4 to 5 square millimeters. Also, before buying the necessary wiring, calculate the required footage so that the wires are enough, and it was unnecessary to join them later.
Experienced electricians are advised to immediately take 10% more cable than calculated. Save your nerves and time.
Now you can move on to junction boxes and cut-off machines. You need as many junction boxes as there are rooms in your apartment, one for each. It will be correct if you run the wire from the cut-off machine separately to each junction box.
Power for junction box
It is worth calculating how much power you will connect to the junction box in each room in order to find out their total power and determine the wire size. The wire of which cross-section needs to be laid from the switchboard to the junction box depends on these data.
If the power of the devices is not more than 3 kW, a wire with a diameter of 2.5 millimeters square is sufficient. For a kitchen, where powerful appliances are mainly concentrated, from the shield to the outlet, you need to lay a wire with a cross section of 6 square millimeters.
The photo shows the correct installation of the wiring in the junction box.
Now it's worth taking stock. If you are not sure that you can cope with this important matter on your own, then you should contact the specialists who will perform the necessary work at a professional level, and you will not have any problems during the operation of the electrical wiring.
Table of power, current and cross-section of wires and cables
| Copper conductors, wires and cables | ||||
| Voltage, 220 V | Voltage, 380 V | |||
| current, A | power, kWt | current, A | power, kWt | |
| 1,5 | 19 | 4,1 | 16 | 10,5 |
| 2,5 | 27 | 5,9 | 25 | 16,5 |
| 4 | 38 | 8,3 | 30 | 19,8 |
| 6 | 46 | 10,1 | 40 | 26,4 |
| 10 | 70 | 15,4 | 50 | 33,0 |
| 16 | 85 | 18,7 | 75 | 49,5 |
| 25 | 115 | 25,3 | 90 | 59,4 |
| 35 | 135 | 29,7 | 115 | 75,9 |
| 50 | 175 | 38,5 | 145 | 95,7 |
| 70 | 215 | 47,3 | 180 | 118,8 |
| 95 | 260 | 57,2 | 220 | 145,2 |
| 120 | 300 | 66,0 | 260 | 171,6 |
| Conductor cross-section, mm2 | Aluminum conductors, wires and cables | |||
| Voltage, 220 V | Voltage, 380 V | |||
| current, A | power, kWt | current, A | power, kWt | |
| 2,5 | 20 | 4,4 | 19 | 12,5 |
| 4 | 28 | 6,1 | 23 | 15,1 |
| 6 | 36 | 7,9 | 30 | 19,8 |