Due to the operation of machines, motors, equipment, etc., industrial processes have both low, medium, and high voltage electrical installations, which represents a latent risk of suffering electrical accidents, as a result of any damage, for more minimal whatever.
For this reason, it is important to know what are the types of electrical accidents to which workers are exposed, as well as what are the factors that intervene in the risk of electrocution and how we can prevent them.
Types of electrical accidents
They are classified into two types:
- Direct: those caused when current circulates through a person’s body, that is, by the immediate consequences of an electrical shock, and this type of electrical accident can lead to ventricular fibrillation (arrest cardiac), respiratory arrest, muscle contractions, burns, and embolisms.
- Indirect: they are not caused by the current itself, but by falls or blows caused after the loss of balance as a result of contact with the current; as well as burns due to electric arc or fires and explosions caused by electricity.
Factors involved in the risk of an electrocution
When electric current circulates through the human body, it behaves like a resistance, so it suffers injuries that depend on the following factors:
The electrical resistance of the human body
The resistance that each person presents to an electrical accident depends on various factors.
- Condition of the contact surface (humidity, dirt, etc.).
- Contact pressure.
- According to the average values of electrical resistance, which is measured in ohms (Ohm), where the maximum is set at 3 thousand Ohm and the minimum at 500, dry skin has a high resistance of 1500 Ohm; for wet skin, the resistance is reduced to 1000 Ohm, in this case, sweating can affect; in wet skin, the resistance is 660 Ohm, while for submerged skin it is 325 Ohm.
- Materials that cover the part of the body that makes contact.
- The resistance of the human being, which depends on age, alcohol levels in the blood, etc.
- Output resistance, which includes footwear and ground.
Form of electric current
It can be continuous or alternating and both follow the principles of Ohm’s law; however, alternating current is three to four times less dangerous than direct current.
- Alternating current: the alteration that it produces to the nervous and circulatory system results in spasms, jerks, and ventricular fibrillation.
- Direct current: acts by heating; it can pose a risk of stroke or death from electrolysis in the blood.
- Applied voltage
- The resistance of the human body varies according to the applied voltage (there are two types) and whether the place is dry or wet.
- Contact voltage: difference in potential that a person could experience through their body, when a fault current occurs and at the same time, they have a hand or part of their body in contact with a grounded structure.
- Fault voltage: it is due to an insulation fault between two masses, between a mass and a conductive element or between a mass and earth.
Frequency of electrical current
The higher the frequency, which we measure in hertz (Hz), the less the danger posed by an electrical accident. Values above 100 thousand Hz are considered practically harmless, since they only produce heating effects without damage to the nervous system, while for values of 10 thousand Hz, the danger is similar to that of direct current.
Path of electrical current
The effects of an electrical accident on a person also depend on the organs of the human body that the electrical current passes through.
- If the electric current enters through the left hand, it will exit through the right foot and vice versa.
- If an electrical current enters through the right hand, the chest (heart) and left hand can also be affected.
- If the electric current enters through both hands, the damage will be to the head.
- If the electrical current enters through the right foot, it will exit through the left foot.
How to prevent an electrical accident?
Although, as we mentioned at the beginning, electrical accidents are a latent risk in the industry, they can be prevented, taking into account the following precautions:
- Make sure that all electrical appliances are properly designed, installed, and in good condition (properly maintained, promptly).
- Place each electrical appliance that will be in contact with the body with its respective earth discharge and plug it into circuits that contain protective equipment
- Determine and clearly mark the three approach limits for the personal safety of the Technical Regulation of Electrical Installations (RETIE), which are:
- Safe approach limit: minimum distance from an energized point of the equipment, up to which unqualified personnel can be safely positioned by the electric arc.
- Restricted approach limit: minimum distance up to which qualified personnel can stand without wearing certified personal protection elements against the risk of an electric arc.
- Technical approach limit: minimum distance in which only qualified personnel, with certified personal protection elements against the electric arc, can carry out work in the area of the direct influence of the energized parts of equipment.
Provide workers who operate in areas with risk of an electrical accident, the corresponding certified safety equipment.