As we can see, there are several fields that have specific functions on the plate. Depending on the product and certification obtained, there are one or more types of certificates such as ATEX certification issued in the Community (EN) and IECEx certification (IEC) or other certification based on the country of destination of the product.

Let's look at the function of each field (reference) below.

Ref. "1" means the year of construction of the product, important to understand which legislation can be referred to, considering that the standards are constantly updated and hence it is crucial to understand the year of construction. It should be noted that products placed on the market do not expire if they are not modified or tampered, since the legislation is not retroactive. But if should be necessary to update the plant part where the product is installed and a new classification of the area concerned, the designer will have to check if the previously installed product is still fit for the new classification and if not, the product must be replaced with another having the characteristics corresponding to the new mapping of hazardous areas. E.g. if previously there were substances that classified the area as ‘Ex d IIB’ and then because of a process variant, it is necessary to have a ‘Ex d IIB + H2’ equipment for the presence of hydrogen.

Ref. "2" means the serial number, which is unique for the product where the plate is fixed or, in the case of identical products and made in a significant lot, that reference shall be repetitive on each product made in that production lot. In fact, it is a manufacturer's obligation to give the product traceability by inserting a unique number for each product, which will allow traceability in time to find any spare parts and to check the authenticity of the product by the Certifying Body.

Ref. "3": The reference indicates which product it is, i.e. the constructive model that can be find in the catalogue and in the certificate, which indicates the typology and its specific features.

Ref. "4": Identifies the certificate number for the product made in accordance with EN standards, thus with ATEX certification. However, it should be pointed out that in the Directive 2014/34/EU, Article 16, paragraph 1, unlike the old Directive 94/9/EC, it is written that the CE mark may be affixed, if it is not possible on the product for its shape, on its packaging and on the accompanying documents.

Ref. "5": Identifies the certificate number for the product made in accordance with IEC standards, thus with IECEx certification.

Ref. "6": Indicates the temperature class of the product.

Ref. "7": Indicates for which ambient temperature has been designed according to the temperature class, i.e. the product can operate up to the maximum ambient temperature indicated in the certificate plate, in order to ensure that the temperature class is respected and that the product not became the cause of the explosion for passing the superficial surface temperature.

Ref. "8": This column shows all the electrical data of the product, such as voltage, current, terminal number and the maximum conductor cross section. These data are essential for keeping the equipment up-to-date and for any need to replace terminals which may have been damaged during assembly at the site, considering that it is possible to replace terminals with other components of equal electrical characteristics, verifying that they have equal dissipation of those installed by the equipment manufacturer.

Ref. "9": Indicates the maximum surface temperature permissible for the product.

Ref. "10": "CE" symbol indicates that the certification is in accordance with Community requirements and that the product is constructed or distributed in full compliance with the requirements of Community Directive 2014/34/ EU.

Ref. "11": the number indicated is the identification number of the notified surveillance body provided for in Directive 2014/34/ EU, which intervenes during the production control phase.

Ref. "12": this is the specific trademark of explosion protection as provided for in Directive 2014/34/EU.

Ref. "13" means the Group to which the product belongs to, i.e. the product is intended for use in places with explosive atmospheres for the presence of gases other than mines with possible presence of grisou. These products are subdivided according to the nature of the explosive atmosphere for which they are intended into IIA, IIB, IIC.

Ref. "14" means the reference category in accordance with Annex I to Directive 2014/34/EU for Group II products.

Ref. "15": indicates the compliance with the specific category of dangerous substance present in the area classified as "G" in case of gas and "D" in case of flammable dusts.

Between the second and the third row, we can find the symbol of a crossed barrel. This symbol indicates that, pursuant to art. 13 of Legislative Decree no. 151 "Implementation of Directives 2002/95/EC, 2002/96/EC and 2003/108/EC on the reduction of the use of hazardous substances in electrical and electronic equipment and waste disposal”. As from 13 August 2005, all electrical and electronic equipment, must be labelled with the symbol of the barrier barrel indicating the obligation not to dispose of WEEE (Waste Electrical and Electronic Equipment) as mixed municipal waste, but to make a separate collection. This specification is also included in the safety instructions attached to the product.

The user will therefore have to give the end-of-life equipment to the appropriate separate collection centres for electronic and electro technical waste or to return it to the reseller upon the purchase of a new type of equivalent equipment, one by one.

Closes the certificate plate the explanation of use quality screws A2(A4)-70 UNI 7323 R 700 N / sqmm, in accordance with the provisions of the certificate. This annotation is essential for the possible replacement of screws in case of loss during installation and/or maintenance. Failure to observe the use of screws as indicated, nullify the sealing capacity to the stress caused by an internal explosion. In this case, the full responsibility for damage things and people is of the installer/maintainer.

Also, for this plate there are several fields with specific functions which refer to the plate of full compliance. Examining it, we note that in the first description above, as in the centre of the plate, it is clearly indicated that this housing or equipment is provided empty and, therefore, inside it there will be no equipment, electrical components and connection terminals. The only object inside, if specifically required by the customer, will be a plate for the housing of the equipment and/or electrical or electronic equipment that the customer will mount. In this case, it will responsibility of who will arrange the product, certify the whole system and affix its certification plate. This condition also applies to components such as mechanical operators and signalling with "U" certification distributed complete with all their accessories for installation.

In the other fields of the plate, as for full compliance, is indicated the year of construction 20…, the type of product, the method of protection and the specification that this type of housing is suitable for housing Ex certified components.

What Ex-Certified Components means?

It means that anyone who goes to equip the enclosure with a component-type certificate must be responsible for complying with all the requirements of the enclosure’s manufacturer or with the certification of the final assembler during all the design and assembly phases. For example: the use of operators, selectors, light bulbs of the enclosure manufacturer or foreseen in the full compliance with the certification of the final assembler; place the equipment inside the enclosure by respecting the surface covering leaving at least the 20% of free space of each section for the method of protection ‘Ex d IIB’ or the 40% of free space for ‘Ex d IIB + H2 and IIC’; the electrical characteristics and all the prescriptions provided in the safety instructions attached to the enclosure.

The incoming/outgoing cables must be executed only with accessories certified in accordance with IEC/EN 60079-0; IEC/EN 60079-1 and IEC/EN 60079-31, as prescribed in the safety instructions supplied along with the product.

After designing the assembly, with one or more enclosures with component certification, the builder of the assembly must be responsible for obtaining the conformity certification of a complete equipment without the need to repeat all type tests, in accordance with the provisions of the Standard.

In this case, the assembly must be marked in accordance with the requirements for the Ex-components marking specified in the EN/IEC 60079-0 Standard, with the manufacturer's name, serial number and identifier.

For this plate too, there are several fields with specific functions.

Let's look at the first description above: we note that it is clearly indicated that this enclosure or apparatus is constructed to contain components for control, signalling and monitoring or more simply to contain electrical or electronic equipment, with a limitation of use, limitation indicated by the extension "X" of the certificate.

The limitations of use are shown in the certificate indicated on the plate. They may be the most varied, the type of test to which the enclosure has undergone during the certification stages, for example, but not limited to (ATEX certificate CESI 01 ATEX 036X indicated on the plat):

• Accessories used for cable entry and to close unused inputs must be certified according to IEC /EN 60079-0; IEC/EN 60079-1 and IEC/EN 0079-31. A minimum IP66 degree of protection must be guaranteed in accordance with IEC/EN 60529.
  
• The command, control and signaling units must be used in the following temperature ranges:
  - From -20°C to + 40°C/55°C: all versions of command, control and signaling units for Group I (stainless steel only), IIC Group and Group IIIC.
  - From -40°C to + 40°C/55°C: all versions of command, control and signaling units for Group IIC and Group IIIC, with polycarbonate signal lamp.
  - From -60°C to + 40°C/55°C: all versions of command, control and signaling units for Group IIC and Group IIIC, without polycarbonate signal lamps.

All limitations of use have not been listed, postponing their vision directly to the certificate.

In the other marking fields, as for full compliance, is indicated the year of construction 20.., the type of product, the method of protection and the specification that this type of enclosure is suitable for housing components for control, signaling and monitoring or, more simply, to contain electrical or electronic equipment, with special conditions for safe use.