Cross-sectional area of home improvement cable how to choose

The choice of cable cross-section size should be based on the maximum residential electricity demand and the maximum current carrying wire and cable can be set. People generally calculate the residential electricity consumption, according to the architectural design code is calculated according to the area of ??40-50W per square meter. This is more than 90 meters above the house can be, for 50-60 square meters of residential cannot meet the requirements. Therefore, the home renovation money should first plan all the residential electricity consumption and then select the wire cross-section. If the general household appliances are included, including air conditioners, refrigerators. Washing machines, TVs, microwave ovens, water heaters, computers and more, leaving only a few years of development margin.

Housing is now generally 4mm2 into the line of copper, so at the same time, the opening of household appliances shall not exceed 25A or 5500W.

Power consumption is relatively large household appliances are: Big 3 air conditioning power consumption of about 3000w (about 14A), (1.2 pound room 5A electric water heater 10A, microwave oven 4A, rice cooker 4A, dishwasher 8A, with drying function Washing machine 10A, electric water boiler 4A, 90% of the fire caused by the power supply is caused by the heating of the connector, so all the connectors are to be soldered, and the contactless components that can not be soldered must be replaced within 5-10 years (such as sockets, air switches, etc.) ).

GB allows long-term current: 4 square is 25-32A, 6 square is 32-40A In fact, these are theoretical safety values, the limit value even greater than these. 2.5 square copper wire is allowed to use the maximum power is 5500W, 4 square 8000W, 6 square 9000W no problem. The selection of home wiring specifications should be based on the total power of household appliances to calculate, and then select the appropriate wire and cable according to the maximum current carrying capacity of different specifications wire, the required current carrying capacity should be calculated according to the following formula: Where:

I = w / uxk

I-line for the maximum current capacity required, in A

W A total power of household electrical energy, unit w

U a household rated voltage in V

K over-voltage safety factor, the value of the general take 1.2-1.3

According to the above formula to calculate the current carrying capacity of household electricity maximum demand current and then according to the different surface of the wire can withstand the maximum capacity to select the appropriate cut off the wire:

1. First, calculate the total circuit load (total power) is the total power of the terminal equipment.

2. Determine the circuit of electric jade, civilian series on 220 / 380V two categories as U, unit V

3. Calculate the total current of the circuit, as I, I = P / U, unit A.

4 Select the type of wire (usually home improvement and minor works mainly copper wire / aluminum, which is divided into single-core multi-core)

5. Straight out of the current capacity of this type of wire (direct access to the wire instructions or test report) as X

6. Conductor cross-section = IX, if there is a decimal point according to a method of calculation if the model wire according to the high model selection

Here's an example:

For example, a residential circuit is calculated that the total load (P) 6KW (the circuit to be connected to the power of the device == equipment can be added) 220V circuit voltage (U then: the total current (I) = 6000W / 220V = 27.27A The circuit uses a single core of copper wire through the wire through the current capacity of about 6mm2 (X) then the circuit should be used wire surface area I / X = 27.27 / 6 = 4.545mm2 According to the law The use of 5mm2 wire access through the wire without 5mm2 specifications close to the model 4mm2 and 6mm2, in accordance with the principle of high on the circuit should be 6mm2 wire.