This course is the first in the BSc programme of building engineering in which the students are introduced to the fields of electrotechnics and electrical installations. The main objective of the course is to provide the students with the fundamental laws of electrotechnics and with the main concepts related to electrical safety and electrical installations in buildings, and in construction and demolition sites. After considering the main components, the course will present the basic techniques for studying three phase systems, in normal and fault operation and the problems of protections against overcurrents and direct and indirect contacts. Part of the course is dedicated to the general safety concepts and their application to electrical plants, including the main references to the most significant legislation and standards for electrical safety and to the prevention techniques. These contents allow graduates in building engineering to interact with experts in the electrical sector, being aware of the terminology, the main problems and the application aspects concerning legislation and electrical installations. This opens wider occupational possibilities in public and private sectors.

Ability to solve electrical circuits governed by the basic laws of electrotechnics. Knowledge of the basic principles of electrical safety. Ability to schematize and solve electrical circuits related to the study of electrical safety issues and to electrical installations in buildings. Knowledge of laws and fundamental standards regarding electrical applications for the construction industry. Knowledge of the operating characteristics and unified sizes of the electrical components used in the electrical installations. Ability to interpret electrical schemes related to the distribution of electricity in buildings.

Knowledge of the basic concepts of Mathematical Analysis, Geometry and Physics. Further prerequisites are notions of complex numbers and a basic knowledge of vector calculus.

Direct current electrical systems [6 h] Elementary circuit. Steady-state regime. Definition of the basic quantities: electrical current and voltage. Passive and active sign conventions. Power and energy. Kirchhoff’s current law (section, node). Kirchhoff’s voltage law (closed-loop, mesh). Two-terminal elements and constitutive relationships: resistance. Short-circuit and open-circuit. Current source and voltage source. Series and parallel of two-terminal elements. Voltage and current divider. Star and Delta connections. Superposition method. Thevenin equivalent circuit. Millmann’s theorem. Practical examples of direct current circuits. Practice: direct current electric systems [3 h] Alternating current electrical systems [6 h]: Review of algebra of complex numbers. Sinusoidal waveforms. Phasor associated to a waveform and properties of phasors. Topological and constitutive equations in the phasor domain. Capacitor and inductor. Impedance, admittance and general form of the Ohm’s law. Main principles and theorems in the phasor domain. Power in sinusoidal steady-state operations (active, reactive, apparent and complex power). Boucherot’s theorem. Practical examples of alternating current circuits. Power factor correction of single-phase resistive-inductive loads. Laboratory: Measurements on alternating current systems [3 h] Three-phase system: origin and definitions (symmetric system, balanced system, direct sequence, inverse sequence, phase, phase-to-phase and line quantities). Star and Delta connection of impedances. Load in series and parallel. Equivalent single-phase circuit. Role of the neutral conductor. Powers in the three-phase systems and their monitoring. Power factor correction (star and delta connection of capacitors). Practice: three-phase electric systems [3 h] Transformer [3 h]: Structure and working principles of the transformer. Model of the single-phase transformer. Model of the three-phase transformer. Practice: transformer [1.5 h] Structure of electrical systems [3 h]: Classification according to the rated voltage. Structure of generation, transmission and distribution power systems. Low Voltage distribution and different types of connection to the Distribution System Operator. Power Delivery Substation and structure of the electrical system in buildings. Power lines, overcurrents and protections [6h]: Electric cables. cable-laying conditions. Thermal current limits of the cables. Definitions of overcurrent, overload and short-circuit. Operation of protection devices (circuit breakers and fuses). Sizing criteria for the electrical installation. Voltage drop. Short-circuit current calculation and choice of the protections against overload and short circuit. Practice: Sizing of the electrical system components in buildings [3 h] Electrical safety [10 h]: Effects of electric current on human body. Electric shock. Safety curves for alternate and direct currents. Resistance of human body. Ordinary and non-ordinary sites. Voltage-time safety curves determination. Dangerous voltages. Grounding systems. Dispersion of the electric current in the ground. Spatial evolution of the potentials on the ground surface. Touch and step voltages. Characteristics of the earth electrodes. Structure of grounding systems. Equipotential connections. Measurement of the resistance of grounding systems. Types of insulation. Definitions of exposed conductive part, extraneous conductive part, direct and indirect contact. Protection against direct contacts. Level of protection of the enclosures (IP code). Protection against indirect contacts. Classification of LV distribution systems (TT, TN, IT) and protection schemes. Residual current circuit breaker. Protection against indirect contacts without circuit interruption (class II devices, electric separation). Extra low voltage systems (SELV, PELV, FELV). Electrical systems in sites with higher electrical risk. Application examples. Exercises: electrical safety [3 h] Electrical systems in buildings and construction sites [6 h] Point of Delivery. Selection of the electrical system components. Electrical schematics for the building electric systems. Control and communication systems. Domotic systems. Regulatory aspects for the electrical systems in the building sector. Laws and standards, unification, certification, declaration of conformity, testing procedures for electrical systems. Analysis of the CEI Guide for the realization of electrical systems in construction sites. Construction sites conditions. Point of Delivery and distribution systems. Power lines. Safety prescriptions. Components for electrical systems in construction sites (switchboards, power plugs and sockets, lighting appliances and systems). Grounding system. System management and testing. Laboratory: verification measurements for electrical systems [3 h] Guided tour of an electric substation [1.5 h]

The course (6 cfu) is structured in 40 hours of theory, 13.5 hours of practical work and 6 hours in laboratory. A guided tour of 1.5 hours of an electrical substation will also be organized. In case the course will be delivered on site the lectures are provided using in part the blackboard and in part slides, pictures and videos. In case the course will be delivered online the blackboard part will be substituted by a digital whiteboard and the written material will be provided to the students. The laboratory experiences will be executed by the lecturer and presented to the students or substituted by software simulations. The guided tour will be substituted by the discussion of pictures and videos.

1. Notes from the lessons and material distributed by the teacher will be uploaded on the educational portal during the course. 2. Suggested books that cover the main part of the course are: · C.K. Alexander, M.N.O. Sadiku, Electric Circuits, McGraw-Hill · Medium Voltage technical guide – Schneider Electric · Electrical installation guide - Schneider Electric · M. Mitolo, Electrical safety of Low-Voltage Systems, McGraw-Hill 3. Collection of exam examples (available on the educational portal)

Modalità di esame: Prova scritta (in aula); Prova orale facoltativa;

Exam: Written test; Optional oral exam;

... The final evaluation is carried out through an onsite written test, lasting 60 minutes. The exam consists of two parts: a part of electrotechnics and a part of electrical installations, lasting 30 minutes each. The two parts have the same weight in the final evaluation. Electrotechnics part: The electrotechnics part consists of theory multiple choice questions, and multiple choice and numerical answers that require the solution of a short exercise. Electrical installations part: The part of electrical installations consists of theory multiple choice questions, multiple choice and numerical answers that require the solution of a short exercise, and short theory and exercise open questions. The scores are different, depending on the type of questions, and are indicated in the text. In case of wrong answer in a multiple-choice question, a penalty of 25% is applied. During the written test, the use of the calculator is allowed. Using other material or notes is not allowed. The total score is the sum of the scores obtained in the 2 parts. Students who have obtained a minimum score of 7/15 in each part and a total score of 15/30 or more in the written test can request an integrative oral exam which allows to modify the score of maximum + or - 3 points. To get the laude it is necessary to do the oral exam. The integrative oral exam, which lasts 15/20 minutes and is conducted in presence, covers the entire programme of the course and consists in a theory question or short exercise for the electrotechnics part and a theory question or short exercise for the electrical installations part.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.