Short circuit in electrical cables, what are the risks?

Currently, all electrical cables are already manufactured with flame retardant material or at least according to standards, they should be. Regardless of whether or not to propagate flame, there are several types of cables that emit toxic smoke, just as there are also cables that do not emit toxic smoke, and that is what we will show and explain in this article, come on guys.

Electrical short circuit: What are the risks?

Electricity, heat, and smoke are very dangerous things when they are not used well! And in the event of a short circuit, these three factors can occur in an uncontrolled way in the same place, causing serious accidents such as a fire, an electric shock or smoke poisoning. That is why in electrical, we always talk about standards, correct calculations and adequate sizing, precisely so that none of this occurs.

The electric short circuit can generate smoke and in more severe cases even fire. Smoke poisoning is very common in these cases and is something extremely serious, which can bring several health complications to the victim. The short circuit is usually caused by overload, where the current is much higher than the cable can handle. In this case, there is an increase in energy consumption in the installation and melting of the PVC jacket of the cables, generating smoke from a burnt wire. To perform these tests we use an isolating transformer that supports up to 300A with 3V at the output, see the image below. With the correct use of this isolating transformer, our short test circuit can be carried out without risks.

Isolating transformer model used in the test

Short circuit in cables: non-toxic smoke

In this first test, the short circuit was on a 2.5 mm² cable that does not emit toxic smoke. During the short, it was possible to notice that it emits much less smoke and it has a white tint. In this test, when we put the pH measuring paper in contact with the released smoke, it remains yellow indicating that the smoke is not toxic, see the image below.

Test short circuit on a cable that does not emit toxic smoke

Short circuit in cables: toxic smoke

In the second test it was a short circuit in a 2.5 mm² PVC cable that emits toxic smoke. During the short, it was possible to notice a large amount of dark and toxic smoke released, and when we put a pH measuring paper in contact with the released smoke, we can see that it got a reddish hue, which indicates the acidity of the smoke, sees in the following image.Short circuit electrical cables

Short circuit test on a cable that emits toxic smoke. See the result on the paper that measures pH.

An important observation needs to be made, in both tests we use only one cable, but we know that in an electrical installation there can be several cables in the same conduit, that is, the more cables, the greater the amount of smoke released and, consequently, the greater it will still be the risk of intoxication. See in the image below the test carried out with 3 cables inside the conduit, note how much smoke is greater.

See the amount of toxic smoke coming out of the conduit after a short circuit

After seeing through these tests the enormous amount of smoke that a short circuit can release, it is easy to understand the risks and how dangerous it can be to inhale toxic smoke! This subject is so serious that there is an entire chapter of the NR 10 standard talking about fire fighting, in addition to several topics of the NBR 5410 standard that also deal with this same subject.

Cables that do not emit toxic smoke, where to use?

Know that the standard requires the use of this type of cable in places where there is a large concentration and circulation of people, such as shopping malls, hospitals, schools and other public places. As a rule, not all places require the use of cables that do not emit toxic smoke, but after the tests that we are going to show, maybe you will rethink this!

As stated during the article, the use of cables that do not emit toxic smoke is not mandatory in your home, but is it worth taking the risk? Despite having a price slightly higher than the cable that emits toxic smoke, this investment is worth it, because we are talking about safety and accident prevention!