Electric current, can I use network cable and telephone cable?

 

Do you think network cable and telephone cable support electrical current? The Electric World brought this article because we have already seen a lot of wiring connection with this type of cable.

That’s why we use a microwave and a transformer to perform an overload test on the network cable and telephone cable. The result we show you now, so come on guys!

Electric current: Telephone cable
In this first test, we used a socket made with telephone cables, and the thickness of these telephone cables is only 0.5 mm². How long do you think this cable will support when connecting a microwave with a current of 10A?

To start explaining how big the risk is, we used a multimeter with a thermal camera to show how the cable temperature rises very quickly after the microwave is turned on, look at the before and after image below.

Sizing of electrical cables
Multimeter thermal camera showing the temperature rise in the electrical cable

After turning on the microwave it took a short time for the plastic cover to melt, that is, it only took a few seconds for this connection to present problems and become a risk for users. In the image below you can see the exact moment when there was a short circuit during the test, this happened when the plastic cover melted.

Network cables and telephone cable
Short circuit in the test with telephone cable

We also tested the phone cable using our 300A transformer! The cable melted and broke a few seconds after the transformer was connected. See how the insulation was and also the part of the cable that broke.

Sizing of electrical cables
Effect of an overload on a telephone cable

Electric current: Network cable
Outra coisa absurda que já vimos muito é unir os fios de um cabo de rede para aumentar a seção, com isso, supostamente é possível usar o cabo para ligar tomadas. Será que isso resolve? Os cabos conseguem mesmo aguentar mais corrente? Usamos novamente o transformador para fazer o teste, e como já era esperado o cabo se derreteu rapidamente, justamente por causa do aumento da corrente. Sabemos que muita gente vai achar que é um absurdo, mas infelizmente existem várias instalações elétricas das tomadas feitas com fios de telefone ou cabo de rede.

Sizing electrical cables
Efeito de uma sobrecarga em um cabo de rede

Bitola dos cabos elétricos
É importante saber que na norma NBR 5410 existem tabelas de dimensionamento onde estão previstos cabos de 0,5 e de 0,75 mm². Uma das tabelas da norma cita qual é a seção mínima de cabos para as instalações elétricas de acordo com as funções. Veja que os cabos de seção 0,75 mm² ou mais finos só devem ser usados em situações específicas como por exemplo, extra baixa tensão ou comunicação.

Network cables and telephone cable
Tabela da NBR 5410 que mostra a seção mínima dos condutores elétricos. Saiba qual bitola usar em cada caso!

These tests that we show only prove why network cables and telephone cables cannot be used in electrical installations for connecting electrical circuits. Remember that safety is very important, and the professional in the Electrical World must always use the correct and well-sized cables to avoid accidents. Before closing, we want to leave an ABRACOPEL graphic that shows that in 2018 there were more than 530 fires caused by overload, that is, cables and circuits were badly dimensioned.

Network cables and telephone cable
ABRACOPEL data on accidents of electrical origin. See the number of fires caused by overload in each region of Brazil!