eLearning courses Rischio elettrico
Our eLearning courses for the training of PES-PAV employees on electrical risk.
Corsi di aggiornamento per Addetti ai lavori elettrici
Corsi di formazione di base per Addetti ai lavori elettrici
What is Electricity Risk?
The electrical risk is the risk due to direct or indirect contact with an active and unprotected part of an electrical system, as well as the risk of fire or explosion deriving from the poor state of maintenance or from the inexperience in the use of systems and instrumentation (Legislative Decree 81/2008) This is therefore a potential risk faced by all the so-called electrical operators: electricians, installers, installers, maintenance workers, but which also extends to workers who work in proximity of plants or electricity sources, even if they do not intervene directly on them.
What is the reference standard for electrical risk?
The assessment of electrical risk is an obligation explicitly introduced by Title III of Legislative Decree 81/08. Although the obligation to assess all risks was already present in Legislative Decree 626/94, today's articulation of Legislative Decree 81/08 specifies the criteria for the assessment of electrical risk and for the identification of the measures of safety, also with reference to the "pertinent technical legislation" (including, currently, the CEI 11-27 edition IV of 2014 and CEI 50110-1 edition III of 2014). The aspects relating to the obligations of companies, and measures preventive and protective, they are defined in Legislative Decree 81/08, in the articles from 80 to 87. In this regard, they deserve special attention.
What is the electrical risk assessment methodology?
Title III of Legislative Decree 81/08, in Chapter III "Electrical installations and equipment", takes up and develops the employer's obligations connected to the presence and evaluation of electrical risk. Specifically, there is the explicit obligation introduced by art. 80 "Obligations of the employer", paragraph 2, charged to the employer, to assess the electrical risks connected with the presence of electrical systems and appliances, taking into consideration three main aspects:
- the conditions and specific characteristics of the work considering possible interferences (and consequent interfering risks);
- the electrical risks present in the workplace;
- all foreseeable operating conditions of electrical systems and appliances.
What are the categories of electrical work?
- Working under tension : electrical work carried out on panels, equipment, or in any case active parts of electrical systems that are live (ie connected, active and in their normal operation)
- Working out of tension : electrical work carried out on panels, equipment or parts of electrical systems normally in operation to which power is disconnected for the execution of work
- Work in proximity : electrical work carried out within a certain distance from the active parts of any electrical equipment in normal operating conditions and therefore in tension.
What training to do for electrical risk?
Legislative Decree 81/2008 provides for the execution of works on live parts to be entrusted to workers recognized as suitable by the employer according to the indications of the technical legislation.
The electrical risk courses aim to provide the worker with the theoretical and practical knowledge of electrical risk on live parts. The employer, at the end of the training course and on the basis of the other elements already in his possession (degree of experience in working on electrical installations out of voltage or in proximity, and / or on low voltage electrical installations under voltage, reliability of the person, sense of responsibility, etc.), will confer, according to CEI EN 50110 - 1 and CEI 11 - 27 Standard, the recognition of Expert Person (PES) or Person warned (PAV), as well as the attestation of " Suitability "to carry out" live work on low voltage systems ".
Which are the professional figures introduced by the CEI 11-27 Standard?
The professional figures introduced by CEI 11-27 are:
- P.ES. (Experts) : A PES is a person with theoretical technical knowledge and with an experience that allows them to analyze the risks deriving from electricity and perform electrical work in complete safety. A PES can carry out electrical work off and near;
- P.AV. (Recognized Person) : A PAV is a person who is aware of the risks arising from electricity and is able to perform electrical work safely. As a rule, a PAV is instructed by a PES or by a person who still has the right technical knowledge;
- PE.I. (PErsona Idonea) : A PEI is a person who has the qualifications to perform all types of electrical work, including live work.
How to check the compliance of electrical installations before the electrical risk assessment?
A pre-requisite for the assessment of electrical risk is the compliance of electrical systems with the requirements of the law, ie the construction of the plants according to the "rule of the art". The verification of the conformity of the plants is an activity that must be carried out upstream of the assessment of the electrical risk and, if it does not give rise to a positive response, it already determines a risk condition for the workers.
How to ensure compliance of electrical installations?
To ensure compliance of electrical installations the employer must:
- a) make sure that the electrical system is installed in compliance with the specific provisions applicable, in particular, that the electrical system is designed and installed in a workmanlike manner, verifying the project documentation and the declarations of conformity issued by the installers or commissioning the plant (requesting the release of the DIRI declaration of compliance with Ministerial Decree 37/08);
- b) make sure that the buildings are protected from atmospheric discharges (art. 84 of Legislative Decree 81/08), or equipped with suitable protection systems against atmospheric discharges, in compliance with technical standards (in particular CEI EN 62305-2); li>
- c) subject the electrical system to regular maintenance and verification based on a control program prepared taking into account the laws in force, the indications contained in the use and maintenance manuals of the equipment included in the specific product directives and those indicated in the relevant technical standards (eg CEI 0-10 guide), proving with appropriate records the performance of this maintenance activity;
- d) subject the electrical system to the scheduled periodic inspections referred to in D.P.R. 462/01 (activity documented by the minutes issued by the verifier).
How to carry out an electrical risk assessment?
To carry out the electrical risk assessment for the workers "Electrical workers" and for the choice of safety measures, the employer must refer to the indications traceable in the CEI 11-27 (IV EDITION 2014) and CEI 50110-1 (2014 EDITION). The Employer must therefore not only assess the risks, and in particular the Electricity Risk, by identifying precise work procedures in safety, but also assigning precise roles and responsibilities to the subjects who will cover these functions, with obvious organizational and supervisory tasks in the execution of electrical works that must be carried out in compliance with current legislation. It should be remembered that an accurate assessment of the electrical risk must be periodically reviewed also on the basis of variations in work processes that can bring about an increase in energy demand, and therefore a potential overload of the plant.
What are the consequences of electrical health risk?
Article 80 of Legislative Decree 81/08, indicates the different types of danger related to electrical risk, distinguishing between direct electrical contact (when the discharge is transmitted to the body directly from an energy source) and the indirect one ( when there is passage of current through a conductive element such as water or metal). Any damage to the organism that may occur following an electrical accident varies according to the duration of the exposure, the frequency and the intensity of the current. One speaks therefore of electrocution (or electrocution) when there is passage of current through the body, in this case it can manifest cardiac damage (fibrillation), muscular (tetanization) and nerve damage with serious impairment of the sensory and motor functions.
Less significant damage can occur due to short contacts or low intensity currents, they are generally located at the point of contact and can occur with local burns or hypersensitivity of the area affected by the discharge.
What is electrocution?
Electrocution is the correct name of the phenomenon best known as an "electric shock", that is a condition of contact between the human body and elements in tension with current flow through the body. A condition necessary for electrocution to occur is that the current has with respect to the body, an entry point and an exit point. The entry point is normally the contact area with the live part. The exit point is the area of the body that comes into contact with other conductors allowing the circulation of the current within the body following a given path. In other words, if accidentally the fingers of the hand touch a part in tension but the organism is isolated from the earth (rubber shoes) and there is no other contact with foreign bodies, the condition of passage of the current does not occur and does not occur records any incident. While if the same circumstance occurs in bare feet there will be electrocution with circulation of the current in the path that goes from the hand to the foot, in this case point of exit. The gravity of the consequences of the electrocution depends on the intensity of the current that flows through the organism, by the duration of this event, by the organs involved in the journey and by the conditions of the subject.
The human body is a conductor that allows the passage of the current while offering, at the same time, a certain resistance to this passage. The lower the resistance, the greater the amount of current flowing through it. This resistance cannot be quantified as it varies from subject to subject, also depending on the different conditions in which the same subject can be found at the time of contact. There are many factors that combine to define it and essentially do not allow the creation of a common reference parameter that is reliable. Among them are sex, age, the conditions in which the skin is found (resistance is offered almost entirely by it), sweating, environmental conditions, interposed clothing, internal resistance that varies from person to person , the physical conditions of the moment, the tissue and the organs encountered in the current path from the point of entry to the exit point.
What is tetanization?
Tetanization is the phenomenon that for the same effect takes its name from a disease of a different nature. Under normal conditions, muscle contraction is regulated by electrical impulses transmitted, through the nerves, to a plate connecting the nerve and the muscle, called the neuromuscular plate. The crossing of the body by higher currents causes, at certain levels of intensity, undesirable phenomena of uncontrollable contraction which reversibly determine the impossibility of reacting to the contraction. For example, the contact between a live conductor and the palm of the hand determines the unwanted and uncontrollable closure of the hand that remains attached to the point of contact. This is tetanization.
What is breathing arrest?
Breathing occurs by inhaling and subsequently exhaling a certain volume of air that repeats under normal conditions about 12-14 times per minute. The individual respiratory acts take place by the contraction of the intercostal muscles and the diaphragm which with their movement vary the volume of the rib cage. During electrocution, for the same reasons that determine tetanization, the muscles contract and do not allow the expansion of the chest, preventing breathing. If the cause of the contraction is not eliminated quickly and assisted breathing is not practiced following an event of considerable intensity, the affected person dies of asphyxia.
What is ventricular fibrillation?
A notoriously delicate organ which is the heart, which bases its functionality on rhythms dictated by electrical impulses, any electrical interference can cause imbalances in the normal pumping action. Depending on the intensity of the current and the duration of the accidental phenomenon, this alteration causes the non-expulsion from the organ of oxygenated blood. This determines the lack of nourishment in the first place of the brain which, unlike other organs, cannot withstand for more than a few minutes without oxygen, without being irreversibly damaged. In this case a timely cardiac massage offers some chance of recovering the injured person, otherwise destined for safe death.
What are burns?
The consequence is the greater the greater the resistance to the crossing of the body by the current which, due to the Joule effect, determines a development of heat. Usually burns are concentrated in the point of entry and in that of exit of the current from the body as the skin is the part that offers greater resistance. As for the other cases, the gravity of the consequences depend on the intensity of the current and on the duration of the phenomenon.