Conformity to a Standard consists of a declaration, made by the Manufacturer and under his own responsibility, that a specific product meets all the requirements of this Standard.
The CE Marking has recently been introduced, according to which the Manufacturer declares that a specific product complies with all the EEC Directives applicable to it. In particular, for electrical material, the applicable Directives are the LOW VOLTAGE Directive (2014/35/EU) on the safety of electrical products and the E.M.C Directive (2014/30/EU) on Electromagnetic Compatibility.
This refers to the set of definitions contained in a Standard and relating to normal operating conditions, construction data, tests, etc.
The requirements are divided into:
These are the standards issued by the following approval bodies:
- IEC International Electrotechnical Commission
This International Commission, in which the most important industrialized countries collaborate, issues recommendations which are taken as a basis by individual national standards
- CENELEC Comité Européen de Normalization Electrotechnique
This Committee issues the EN standards to which European countries refer.
For example, the Standards issued by the following approval bodies:
- CEI Italian Electrotechnical Committee, Italy
- VDE Verband Deutscher Elektrotechniker, Germany
- NF Normes Françaises, France
- CSA Canadian Standards Association, Canada
- UL Underwriter's Laboratories, United States
- BIA-BG Berufsgenossenschaften, Germany
- GOST Gosudarstvennyj Standart, Russia
In some countries, the approval of electrical materials is required by law.
It consists of a Certificate of Conformity to the Standard approved no longer by the Manufacturer, but by an officially recognized independent laboratory.
Each approved device must bear the approval symbols, for example CSA or UL. For the United States, a distinction must be made between two different levels of acceptance:
- RECOGNIZED = The device is marked with the UR monogram only and can only be installed in the electrical equipment by qualified personnel who are well aware of the product's limits of use. On the other hand, the individual sale of the appliance as a general use product is not authorised.
- LISTED = The device is marked with the UL monogram flanked by the approval symbol and can be either mounted in the electrical equipment or sold individually as it complies with all the requirements of the standard.
Mechanical switching device with the function of controlling the operations of equipment, including signals, interlocks, etc.
Therefore position or safety switches, microswitches, buttons and foot switches are part of the family of control auxiliaries.
The Standards define a certain number of categories relating to the normal uses of switches. Each use category defines the current and voltage values (expressed as multiples of the respective nominal values) corresponding to the various load closing and interruption situations.
Succession of two operations with passage from the rest position to the working position and vice versa.
Set of conductive parts (auxiliary contacts) of a circuit breaker intended to be inserted in a circuit separate from the main circuit and from the circuit breaker control circuit. It is intended for supplementary functions such as signalling, interlocking, measuring, regulating, etc.
Electric circuit, distinct from the main one, which is responsible for the circuit-breaker closing or opening operations, or both.
Set of conductive parts (main contacts) of a switch inserted in the circuit that it is intended to open or close.
Maximum current that the circuit-breaker can withstand during a specific short period of time and within the specified conditions of use and behaviour.
Current that characterizes the switch according to the conditions of use defined mainly according to the nominal voltage, the category of use and the type of service.
Maximum current that the switch is able to withstand for a duration of 8 hours without the overtemperature of its various parts exceeding the value set by the standards.
Ratio of inductance to resistance, i.e. L/R = mH/Ω = ms.
The shortest distance allowed between two conductive parts
The shortest distance allowed between two conductive parts laid on a surface of insulating material.
Number of operations under load that the contacts can carry out without maintenance. According to the usage category, it is determined by the rated current and voltage.
Number of no-load operations, i.e. without passage of current, that the circuit-breaker can carry out before overhauling or replacing mechanical parts becomes necessary.
Fixed or mobile parts, conductive or insulating, of an auxiliary control necessary to close or open a single conductive path of a circuit
Contact element that opens or closes the conductive section of its circuit at two points placed in series
Contacts belonging to the same contact element, but adequately isolated from each other so that they can be connected in electrically separate circuits