Copper or aluminum wire to choose for wiring? Choice of wire: aluminum or copper - for and against
For electrical wiring, choose, as a rule, an aluminum or copper cable.
Advantages of copper cable
Why do many prefer a cable with copper "stuffing"? The fact is that copper has a slightly better electrically conductive properties. In addition, the life of copper cables is much more than aluminum, which are suitable for no more than 20 years.
Despite the fact that the copper cable is somewhat more expensive, it is much more reliable than aluminum in operation. The copper cable can withstand up to 80 bends, while the aluminum cable will survive only 12 bends. However, this does not play a role when the cable is laid in the wall, because there the cable should not experience bending.
The aluminum cable is suitable for temporary wiring. Due to its low cost (a small cost is at least three times cheaper than copper cable), this type of cable can be significantly saved. http://steroids-shop.com.ua/product/251/
Today, German manufacturers offer the attention of the consumer high-quality aluminum wires treated with a special paste that protects the wires from oxidation of various kinds. Such pastes make aluminum cable much better than multi-stranded copper.
However, the use of a cable depends also on the purpose for which it is used. Each electrical appliance has its own power, which will directly depend on the cross-section of the cable, and hence its filling.
Specialists developed a simple condition. 1 square millimeter of aluminum cable will withstand a load of 1 kW, copper cable - 2 kW. To determine the cross-section of the cable, you will need to know the power of each electrical appliance. If you do not understand the instruments, it is enough to look in the technical passport of the electrical appliance itself or on the infanal stick.
A copper wire with a cross section of 4 square millimeters is more suitable for a connected electric furnace. However, an ordinary outlet has enough cable cross-section of 2.5 square millimeters. In addition, it is necessary to remember that the usual switches and sockets require the connection of a two-wire cable, and the outlets are electric and with a grounding contact - three-core.
If you are replacing the wiring, you need to disassemble by groups any electrical appliances, having in advance thought out where in the house the most powerful ones (for example, a water heater, washing machine, electric stove) will be located, and in which - the least powerful ones. Remember, at 1 electric wire the load should not be more than 4-5 kilowatts.
If you plan to use an aluminum cable, the size of its section should not be less than 6 square millimeters.
If you have a house older than 20 years, with it in it aluminum wiring - replace it, because the life of aluminum is just 20 years. With the passage of time, this metal loses its plasticity and at any time can be destroyed under the influence of external factors. It is better to do new wiring with a copper cable.
Typically, the wiring standards for luminaires and chandeliers require a copper two-wire cable, more sophisticated appliances (requiring grounding, for example, washing machines, computer, water heater) require the use of a three-core copper cable. Separate wiring requires kitchen electrical appliances. For it, it is advisable to use a copper three-wire cable up to 4 square millimeters.
If you have decided on the type of cable that is right for you, be sure to check the quality of the product for durability before making a purchase. Cable from any metal should bend well. If the seller has given you a huge number of certificates, but does not test the cable for strength by flexing - do not buy such a product, since the seller himself doubts its quality!
If you depart from practice and plunge into theory, then it should be noted that there is much better conductivity in gold, but such conductors are very expensive. The purchase of gold for what would make a conductor will be very expensive. In addition, it should be noted that cables made of such metal are more prone to theft than copper. With the second purchase of gold, and then the production of cable, etc. there will be a similar process - the buying of gold by a pawnshop, and then selling it to you ... Apparently, these arguments are utopian and do not have anything in common with the practice of using industrial cables.
Quite often, when overhauling an apartment, you have to partially modify or change the electrical wiring. Of course, this is a business that only a professional who has the necessary knowledge, skills, experience and permits should deal with. We will try to understand the practical side of the question, and understand, copper or aluminum wire it is better to choose for modern wiring in a dwelling.
To begin with, we abstract away from external factors and try to find out which copper or aluminum wire has higher characteristics. Initially, I would like to note that copper has greater strength in comparison with aluminum, it is softer and because of this it does not break at bending and twisting, which is not uncommon and happens when laying electrical wiring, especially hidden. In addition, copper is less susceptible to chemical reactions, for example, oxidation, while aluminum in the place of twisting is often oxidized, which leads to poor contact and a break in the network. Yes, and the electrical conductivity y copper wires much more than aluminum, respectively, with the same cross section copper wires can withstand a greater load than aluminum.
Proceeding from all of the above, it is possible to draw an unambiguous conclusion that copper wires for all physical properties surpass aluminum ones. However, it should be noted that according to the norms of twisting in electrical wiring is strictly forbidden, respectively, the problem of oxidation is partially eliminated, and the high cost of copper wires, quite often makes their use impractical in cases where it is possible to pick up aluminum wires of suitable cross-section that can withstand the necessary load.
In addition, in Soviet-built houses, when laying electrical wiring used, in almost 100% of cases, aluminum wires. And if you really change them to copper, then it's worth doing only if all the wiring changes, down to the switchboard. Otherwise, there may be a situation that the wiring in your apartment can withstand heavy loads, in comparison with the cable that will feed it from the main route, which of course does not make any sense.
We think, considering the foregoing, each for himself will make the conclusion that a copper or aluminum wire is chosen for laying electrical wiring in his home.
I would like to note that the contact of copper with aluminum should be carried out only through the third metal, otherwise such a connection can not be considered reliable, because The contact of these 2 metals is oxidation.
Choice of wire: aluminum or copper - for and against
Thinking about something high and knocking down the old plaster in the kitchen with the hammer and chisel, I came across a wiring. Immediately remembered the respectable age of the house and, as a consequence, there was an irresistible desire to disrupt all opened old electrical aluminum wires and replace them by laying the wire with a copper core. I already put forward fridge snaige , to carry out my plans ... However, my desire immediately evaporated, as soon as I counted how much it would cost me to buy a copper wire. In the conditions of a limited budget for repairs, the price of a copper wire was, to put it mildly, high.
Then I decided to compare aluminum and copper wire and understand: why in former times such popularity among builders was used by aluminum wiring, with the laying of which already with the connection aluminum wires problems began ...
So which wire is better: copper or aluminum?
1. Copper wire is more durable. It's a delusion. According to the data of any directory, the service life of the wire from both materials is the same: 15 years for wires with single and 30 years for wires with double insulation.
2. Aluminum is rapidly oxidized. Yes it's true. From the school chemistry course it can be recalled that aluminum is a very active chemical element, it reacts instantly with oxygen, forming an oxide film that isolates it from the environment and prevents further decay. Thus, oxidation below this film does not occur and the conductive properties of aluminum, like copper , will please you for many more years. And for those who want to achieve a good contact on aluminum, terminal blocks are produced with a special conductive paste that, when connected, "rips off" the oxide film and seals the place from the penetration of air.
3. Copper is more durable with multiple folds. It is impossible not to agree! According to GOST, copper single-core wire must withstand 80 bends, and aluminum only 12, but ... This difference does not matter for wire laid in the gate or on the wall under the plaster!
4. The price of a copper wire. According to my calculations, an aluminum wire with a cross section of 4.0 mm 2. by load capacity (32 A) can be equated to a copper wire cross-section 2.5 mm 2. (30 A). The cross-section of the wire is the area of the sheath of the conductor. If the cut is round and consists of one wire, then the area of the section is determined by the formula of the area of the circle: Pi (3,14) multiplied by the radius in the square. If the wire is stranded, then the cross-sectional area is found as the sum of the cross sections of all strands. A two-core copper wire of the specified cross-section in PVC insulation costs 8.10 UAH. per meter, whereas the price of aluminum wire, designed for the same load - 2.45 UAH. per meter. The difference is 3.3 times!
5. Resistance of a copper wire is less, than resistance of a wire of aluminum. I do not argue, but let's count, as the hero of one children's cartoon said. Resistivity copper is 0.0175 Ohm * mm 2 / m, and the specific resistance of aluminum is 0.028 Ohm * mm 2 / m. The resistance of a conductor with specific resistance p, length l and cross-sectional area S can be calculated by the formula: R = p * l / S. Thus, a copper wire with a cross section of 2.5 mm 2 and a length of 1 m will have a resistance of 0.007 ohms. The aluminum wire with the same load capacity should be 4.0 mm2 and then the resistance of 1 meter of such wire will be ... also 0.007 Ohm. No difference. But seriously, the losses in the apartment wiring on the resistance of the wires will be less than on any oxidized contact group of outlets.
6. To connect aluminum wires is more difficult than copper ones. I can argue. With today's level of electrical appliances (terminal blocks, end caps, conductive and sealing pastes, soldering and welding, finally) this is not a problem. I would like to focus more on the fact that in no case is a direct connection of copper and aluminum wires allowed! Connect aluminum and copper conductors only through the terminal strip, and so that there is no contact between copper and aluminum.
This is due to the fact that, due to certain physical processes at the point of contact of copper with aluminum, resistance increases significantly with time. As a result, there is a strong heating of the joint, which destroys the insulation of copper and aluminum wires, which can lead to a fire. By the way, this effect is possessed by all materials with different resistance. Therefore, even if you use wires from the same material, in your opinion, it is desirable to twist the wires of the same cable manufacturer. This is due to the fact that factories can use as raw materials not only copper or aluminum, but also various alloys similar to them, but worth less. That is, if necessary to connect cables from different materials, it is best to use terminal blocks or solder / weld.
In this way, for the consumer, the difference in price is important first, and that with time, when changing chandeliers, copper wires do not break off so quickly. Thinking about using an aluminum wire or a copper wire and considering all the pros and cons, I decided to stop for the time being on the aluminum wire.
UncleRem
