Not everyone has the opportunity to replace the old aluminum wiring with a new copper one. The cost of the popular VVG is not so low, especially if it needs to be laid for several hundred meters. But it is still necessary to change aluminum, otherwise the consequences will not be long in coming, given the fact that the service life has long exceeded all expected limits.
Why does aluminum wiring "burn"?
To answer this question, you need to look at the table of specific resistance of materials, in which we will see that this indicator for copper is 0.017 Ohm / mm2, and for aluminum 0.028 Ohm / mm2. That is why, when choosing wiring, aluminum wires should be taken of a larger cross section than copper ones.
Another big problem with this noble metal is rapid oxidation. And the oxide film has a sufficiently high resistance to prevent the passage of current. Due to oxidation, excessive heating occurs at the junction of conductors, sparks may appear, and in the worst case, fire.
Aluminum wiring is the first and main reason junction boxes, switchboards, sockets and switches light up.
During prolonged heating, for example, due to too high consumer power, aluminum quickly reaches the temperature at which the insulation simply "drains". An exposed core dramatically increases the chances of a short circuit. But the most dangerous is the junction of the aluminum conductor and the circuit breaker, here oxidation occurs much faster.
Are there any advantages to aluminum
There are, but they are so insignificant that they should not be taken seriously. For example:
- Aluminum is a light metal, therefore, the process of its transportation and subsequent laying is greatly simplified.
- Lower price than copper conductors. But not that quality either. And given that the cross-section of an aluminum cable should be larger than that of copper, the final figure comes out the same as the purchase of conductors made of "yellow" metal.
Unfortunately, this is not enough to tip the mind towards aluminum wiring. This metal, in addition to rapid oxidation, becomes more fragile every year of operation. From many electricians, you can hear that when dismantling old wiring, aluminum "just disintegrates." Crumbles like a foam sheet.
When installing aluminum networks, it should be remembered that the slightest damage to the core will lead to its breakdown or break in the future. Therefore, you should be extremely careful to clean the insulation from such conductors. And in order not to violate the integrity of the cores, it is better to take the largest possible angle when bending the cable.
Where can aluminum wires be used?
When installing temporary wiring. Here, aluminum is indispensable: it is both cheap and not a pity in practice. Many craftsmen at the rough stage often use aluminum removed during dismantling in old apartments or private houses. In the event of a breakdown or serious damage to the insulation of such "recyclable materials", it can always be sent to the nearest trash can. Without any twinges of conscience.