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04 March 2024

The legislative impact on systems engineering: the Good engineering practice

The legislative impact on systems engineering: the Good engineering practice

In the complex universe of civil electrical systems, ensuring safety and efficiency requires a thorough understanding of regulations and recommended practices. In this short course, we will try to explore in detail the critical issues and advantages associated with design and installation in the residential sector, providing crucial insights for professionals in the electric sector.


Basics and objectives: electrical safety

In general, ensuring safety and efficiency in electrical systems is the main task and objective of a professional, whether installer or designer.
And the civil sector is no exception; in fact, when operating in places in which people live, the safety requirement is essential.


Good engineering practice: the legislative impact on systems engineering

To understand the importance of this activity, it is essential to examine the legislative impact that has characterised the sector over the last fifty years.

In fact, Law 186 of 1968 introduced, for the first time, the idea of "good engineering practice", which acts as a guiding light for all operators in the electric sector. This document, through article 1, clearly imposes the obligation to adopt the best technical and scientific standards in the design and installation of civil electrical systems, also confirming (in article 2), the key role of the Italian Electrotechnical Committee, whose standards are in fact a tool to best fulfil this type of activity.

The need to increase safety and adapt to technological progress then led to the creation of a new essential document for professionals in the electrical sector: Law 46 of 1990.

With this new tool, some obligations related to the submission of technical documentation were introduced for the first time, a practice that aims to raise awareness and make all those involved in the design and installation of electrical systems aware and responsible, also in accordance with the Law.

However, to date, the closest reference in terms of legislation is Ministerial Decree 37/08, which regulates, among other things, low voltage electrical systems. There are many innovations that impact the professional, but in terms of design and installation, a classification of the systems with respect to their intended use (homes, offices, public places, etc.) is introduced, as well as specific safety requirements and criteria for assessing the conformity of the systems. Such conformity must be the result of careful checks prior to commissioning, documented with appropriate Certification tools (Declaration of Conformity).

Ministerial Decree 37/08 therefore plays a key role in ensuring practical compliance with good engineering practice; it is therefore not merely a legislative framework, but an adequate analysis of the document will allow us to examine the tangible impacts of Ministerial Decree 37/08 in the field, the compliance of which translates into reliable, durable systems in line with the best practices in the sector.


From law to field: Ministerial Decree 37/08 and the role of the installer

As already mentioned, the legislative document first of all imposed a precise classification of systems and, consequently, an equally close relationship with the qualification of the professional in being able to work on these types of systems, which include, in brief:

a) systems for the production, transformation, transport, distribution, use of electricity, systems for protection against atmospheric discharges, as well as systems for the automation of doors, gates and barriers

b) radio and television systems, antennas and electronic systems for the management and distribution of TV, telephone and data signals, also relating to security systems, including fibre optic systems, as well as the infrastructures necessary to house such systems (this item, in accordance with technological developments, was amended by Ministerial Decree 192 of 2022)

c) heating, air conditioning and refrigeration systems of any nature or kind, including systems for the evacuation of combustion and condensation products, and room ventilation

d) water and sanitary systems of any nature or kind

e) systems for the distribution and use of gases of any kind, including systems for the evacuation of combustion products and room ventilation

f) systems for lifting people or goods by means of lifts, hoists, escalators and the like

g) fire protection systems


Where do the installer's responsibilities begin?

Therefore, it is clear that the object of interest for professional electricians are systems pertaining to letter A and, secondly, those pertaining to letter B (mainly concerning electronic systems found in homes and elsewhere).

But where does the activity, and therefore responsibility, of the professional begin?

In this case too, Ministerial Decree 37 establishes the existence of a supply delivery point, i.e. a point where the supplier or distributor makes electricity available to the user (usually located at the property boundary and directly accessible from public roads); upstream of the connection point, ownership and functional competence are the direct responsibility of the DSO (distribution system operators), while downstream the responsibility lies with the user and, consequently, this is where the responsibility of the professional begins.

The details and specifics of low-voltage grid connection are defined by IEC 0-21, whose main task is to define the technical rules for the connection of active and passive Users to LV grids; a Standard, whose latest version dates back to 2022, but which in January 2024 saw the introduction of the second Variant (the first had already been approved in November 2022).

It is an essential document for the evolution of grids and their operation, and to prove this, the latest variant introduces changes concerning storage systems and the futuristic V2G, thus anticipating a major trend in the field of energy management.

We have thus defined "the beginning" of the professional's activity in the electrical field (letter A), but is there some sort of parallelism for the electronic world?

In fact, the spread of fibre optics has led to a necessary reassessment of the legislative tools (we have already seen the changes made to DM 37), introducing new definitions that are useful for the plant engineering sector.

Legislative Decree 259 of August 2003 had already clarified the idea of network termination point, i.e. the physical point from which the end user has access to a public electronic communication network; but the most "revolutionary" document for this sector is Presidential Decree 380 of 2001.

As of 1 July 2015, in fact, Law 164/2014 brought into force Article 135 bis of Presidential Decree 380/2001, which, in short, introduces the obligation, in the event of new construction or significant renovation of a building, to provide high-speed fibre optic ultra-wideband connection, i.e. the obligation to provide a passive multi-service physical infrastructure inside the building, consisting of adequate installation spaces and high-speed fibre optic communication systems up to the network termination points, i.e. the entire complex of installations inside the buildings containing wired fibre-optic access networks with fixed or wireless termination that provide access to ultra-wideband services and connect the building’s access point to the network termination point.


Letter A, letter B and project: competences and obligations

Having therefore said that there is a difference in roles and approaches between electrical and electronic systems, in reality, with the amendment of Ministerial Decree 37 (December 2022), a substantial innovation and "rapprochement" between the two sectors was introduced.

In fact, Article 5 requires, for the installation, transformation and expansion of systems pertaining to letters A, B, C, D, E and G, (according to the classification of Article 1, paragraph 2) the drafting of a project, the responsibility of which lies with a professional registered in the professional registers or, alternatively, with the technical manager of the installation company.

But what are the installer's limits? When is the intervention of a qualified professional necessary? And how does the obligation change with the latest amendment to DM 37?

In the residential sector, the intervention of an installer is only possible if two conditions are met: all condominium users or domestic users of individual housing units do not have a committed power exceeding 6 kw or, in the case of domestic users of individual housing units, the total surface area does not exceed 400 square metres.

Outside these limits, a professional registered in the professional registers must intervene, regardless of the competence of the technical manager of the installation company.

Attention: it is always useful to remember that the professional (expert or engineer) will be responsible for drawing up the design of the electronic system if the it coexists with an electrical system.


In this first in-depth study, we have tried to understand the aims, limits and responsibilities of an installer working in the residential sector. Of course, the installation activity must be carried out according to good engineering practices, thus following the dictates of some of the most significant regulations for this type of system: first of all the IEC 64-8 Standard, in particular chapter 37, in addition to the IEC 64-53 Guide (whose fourth edition was published in 2024).

We will examine these aspects and other more specific requirements in future articles dedicated to the design and installation of civil electrical systems.