How to calculate the cross-section of the cable for power

When necessary calculation power cable cross-section for

design, calculation of conductor cross-sections for the intended load and wiring in our city apartments have done for us, professional designers and builders.As far as evaluation correspond to modern realities - it is another question.Stroebe concrete walls and make a new layout of electrical wires for such cases in this article we will not.Let us turn to the private sector, where many fascinating works Active Citizens try to make their own hands.

question is rather rhetorical.Always, when the electric grids connected external consumers of electricity.In the industrial and major housing problems are solved by specialists at the draft stage, in this case will act as calculators dear gardeners, gardeners and owners of private homes.

consider three typical cases, when all they wonder: how to calculate the cable cross-section and buy the correct wire without overpayments and to guarantee long-term operation.

• Forced replacing old wiring that fail as a result of melting, the destruction and aging.The situation is familiar to the old country houses, where the calculation of cable load (if any) does not correspond to modern conditions.
• Replacement distribution switch board or a machine for electrical, designed to improve the operation of electric systems in the house.It is bad when an electric kettle and a microwave together cut down electricity in the house.Circuit breakers are selected with a margin, and the wire can not withstand the load.
• Wiring of electrical networks in the new country house.This is another story, the example of which we will try to explain how to calculate the cross-section of each cable that will eventually illuminate, heat and feed your family.

Initial data for the calculation of the power cable

First of all, let's define what kind of power is at stake.Distributed to your structure, electricity is of no importance, for the calculation of cross-sections of wires of internal wiring is necessary to know the power consumption of all electrical appliances located in the house.For convenience, we divide them into three groups (which, by the way, it makes sense to put on the individual machines RCD).

• Lighting.Power unstable, so to calculate the cable cross-section of this group for frequent houses of residence is better to take the starting value of the simultaneous consumption of all lighting and 100W per lamp.
• Appliances.Calculate the total capacity of the group and the relevant section of the supply cable is not as easy as it seems at first glance.The passport of each instrument is usually given as the minimum and maximum power consumption.Washing machines, electric cookers and other appliances work in different modes, but will have to take into account the maximum values ​​adjusted for peak start jump.
• Electric.Water heaters, underfloor heating system, heating electric boilers, electric heating - the most energy-intensive consumers, plug irregularly, but sometimes for a long time.The calculation of the cable cross-section is better for them to make the load.

Cable Sizing power

Additional information that you need, is simple: the material wires (copper or aluminum), and the characteristics of your network (220V or 380V).Having defined the total power consumption for each group and using this value, you are using simple cross-section of the EMP table is the correct cable.However, with a minor amendment.

example.Copper wire, 220V network, the total electrical power of 10.2 kW.In Table 1 the closest value for open wiring is 9.8 kW, and the cross section 2 mm², be sure to take a margin, iefollowing 2.5 square millimetersFor closed similarly.

Table 1. Open wiring

S	Copper wires	Aluminium wires
mm2	current	Moschn.kVt	current	Moschn.kVt
A	220	380	A	220	380
0,5	11	2,4	-	-	-	-
0,75	15	3,3	-	-	-	-
1	17	3,7	6,4	-	-	-
1,5	23	5	8,7	-	-	-
2	26	5,7	9,8	21	4,6	7,9
2,5	30	6,6	11	24	5,2	9,1
4	41	9	15	32	7	12
5	50	11	19	39	8,5	14
10	80	17	30	60	13	22
16	100	22	38	75	16	28
25	140	30	53	105	23	39
35	170	37	64	130	28	49

Table 2. Closed wiring

S	Copper wires	Aluminium wires
mm2	current	Moschn.kVt	current	Moschn.kVt
A	220	380	A	220	380
0,5	-	-	-	-	-	-
0,75	-	-	-	-	-	-
1	14	3	5,3	-	-	-
1,5	15	3,3	5,7	-	-	-
2	19	4,1	7,2	14	3	5,3
2,5	21	4,6	7,9	16	3,5	6
4	27	5,9	10	21	4,6	7,9
5	34	7,4	12	26	5,7	9,8
10	50	11	19	38	8,3	14
16	80	17	30	55	12	20
25	100	22	38	65	14	24
35	135	29	51	75	16	28

As you can see, everything is quite simple, if you are at a preliminary stage correctly decided on the appetites of your electric friends.