Accidents involving electricity, including electric shocks, overload fires and other discharges, reached 759 in the first half of 2021, according to recent data from the Brazilian Association for Raising Awareness of the Dangers of Electricity (Abracopel). These figures confirm the reality that energy, whatever it is, is dangerous and can cause serious consequences.

Given this information, it is necessary to consider possible situations that can cause risks such as those mentioned above and to know the best way to deal with them, as is the case with electric arcs.

When an electric current flows between two points where loss of insulation and dielectric breakdown has occurred, there is not only visible energy released. Nesta situação, acontecem várias ondas de diferentes comprimentos. “For this phenomenon to happen, there need to be two conductive electrodes, i.e. two points with a potential difference, and between them a gas or insulator that undergoes a dielectric rupture capable of breaking the insulation and producing a discharge,” explains Castellane Ferreira, engineer and director of Varixx, a manufacturer of power electronics solutions.

Among the many risks posed by electrical energy, electric arc stands out as one of the most dangerous for operators and those involved in electrical maintenance. Because of the large amount of energy released and the high temperatures generated by this phenomenon, workers can suffer serious burns or even death. Also, its effects are even more far-reaching, as toxic metal fumes, molten metal projection, intense light and a pressure wave are generated.

“In addition, the light emitted and the frequency spectrum of the electric arc include ultraviolet radiation, which can cause damage human eye retina,” explains Ferreira.

The electric arc can generate heat so intense that it reaches up to 20,000 °C, a temperature higher than any known material can withstand. It can also cause irreparable damage to machinery, equipment and the environment, resulting in economic losses and social environmental liability.

The faults that cause an electric arc are mostly associated with phase-to-ground short circuits, which can suddenly evolve into a three-phase short circuit, and the most common causes of these faults are dropped tools, accidental contact by maintenance staff, accumulation of corrosion or dust on the conductors, aged insulators and the presence of pests such as rats, snakes or other animals that come into contact with energized conductors, which can produce intense heat, explosions, pressure waves and other effects. Because it releases a large amount of energy in a short space of time, electric has come to be considered one of the main risks involving electricity.

“Every day here at Varixx, industries and companies of all sizes and from many different segments come to us to report events involving electric arcs. Often, these same industries wait for something really serious to happen before they take action, and when something of this level occurs, substations with several panels and switchboards are destroyed, impacting the production process and, even more drastically, taking people's lives”, comments Ferreira.

The expert says that this amount of energy diffused in the form of light and heat, in some cases, can have its designed applicability, which is very important for processes that make controlled use of the electric arc, for example, in electrical equipment such as some types of lamps, welding machines, arc furnaces, spark plugs, among many others. Therefore, generalizing that the electric arc is always harmful is not true.

How to minimize the effects of Electric Arc – In fact, companies used to provide protective clothing as a good way of minimizing the effects of arc flash on workers in electrical services. However, for operations in high-risk areas, the level of protection provided by PPE was often not enough to protect the lives of these people. Regulatory standard NR-10, Safety in Electrical Installations and Services, presents a set of measures that, if put into practice, reduce the possibility of a worker suffering the consequences of an electric arc. From de-energizing the panel to the use of EPCs and PPE, collective and individual protection measures that help prevent an electric arc from happening, or minimize its consequences.

Thus, a lot of research has brought technical information on how we can reduce the effects of electric arc or how we can reduce the incident energy generated by this event. For a long time, researchers have developed the control hierarchy pyramid with a step-by-step approach to reducing and protecting people in electrical substations or other high-risk areas. Eliminating risks is the first step. The second is to replace the old equipment with newer, higher-performance equipment, which is applied to circuit protection and opening systems, such as a circuit breaker, for example. After this, the next step is the engineering analysis and the last step is the PPE specification.

Regarding engineering analysis control, Ferreira says that among the existing measures are protection systems that detect electric arcs through ultraviolet waves produced in the initial stage of arc ionization. These systems are able to open circuit breakers and disconnectors quickly after identifying an arc in advance, acting in ultra-fast time. Therefore reducing the energy incident on electrical installations.

The innovative pre-arc time detection mode and ultra-fast actuation in a maximum of 300 microseconds has been introduced for the first time by Varixx. Zyggot Arc performs this detection which eliminates the need for an electric current reading to confirm the arc event. This is possible due to ultraviolet wave detection, which also brings greater reliability, because during the consolidation process of the initial stages of an electric arc, there is an abrupt increase in the ultraviolet wave in the air ionization stage.

“As a result, Zyggot's innovations are considered one of the best on the market, because they increase safety, minimize damage to equipment and prevent risks involving professionals, including death,” says Ferreira.

Electricity is a risk, not only to the lives of employees working in the area, but also to the entire infrastructure of a company and also to its corporate image associated with bad exposure from accidents at work. So watch out for the signal and take preventative measures so that they don't have to be applied after an accident has occurred.