The Foundations of Conformity Assessment systems used in Mexico

UL de Mexico, S.A. de C.V. uses specific procedures when evaluating product compliance. Such procedures are based on the Federal Law on Metrology and Standardization (LFMN – Ley Federal sobre Metrología y Normalización), its Conformity Assessment Policies and Procedures (Políticas y Procedimientos para la Evaluacion de la Conformidad), MNX-EC-065-IMNC-2000, and UL requirements.

These documents can be accessed on the Secretary of Economy site, General Directorate for Standards (DGN – Dirección General de Normas).

Legal frame for Mexican Official Standards (NOM)

This gives a brief overview of regulations. Please contact us for a more indepth discussion and deeper detail.

Constitution of the United States of Mexico

Article 73. The Congress has the power:

XVIII – To establish mints, to fix the standards of coins and coinage, to determine the value of foreign currencies, and to adopt a general system of weights and measures.

Comments: The text above established the mandatory compliance with the International System of Units (SI) specified in Article 5th of Federal Law on Metrology and Standardization (LFMN – Ley Federal Sobre Metrología y Normalización).


This law states the following:

Article 52. All products, processes, methods, facilities, services, or activities must comply with the Mexican Official Standards.

Article 53. When a product or service must comply with a Mexican Official Standard in particular, similar products to be imported must also comply with the specifications stated by such Standard.

For that effect, products or services to be imported must be certified or authorized by a competent authority that regulates the corresponding product or service, or by an accredited and approved individual working with a competent authority, according to what is stated in this Law.

If no applicable Mexican Official Standard exists, competent authorities may require that products or services being imported comply with the international requirements enforced in the country of origin or, if inexistent, those enforced by the manufacturer.

Comments: Therefore, these articles state that products must be certified according to existing applicable Mexican Official Standards.

Foreign trade law

Foreign trade laws establish – articles 4, III; 4, IV; 5, III; and the articles contains in Title IV, Chapter II – measures of non-tariff regulation and restriction of foreign trade applied to exporting and importing commodities, according to agreements issued by competent authorities; being the Articles 17, 17A, 20 and 20A which state LFMN enforcement and the applicability of certificates of compliance.

Article 17. The measures of non-tariff regulation and restriction to the export and import of commodities, to that fraction III of the article 4 refers, will have to be established, where appropriate, by agreement of the Secretariat or jointly with the competent authority. These measures will consist of previous permissions, maximum quotas, marked by country of origin, certificates, compensatory quotas and the other instruments that are considered suitable by the parameters of this law.

Additionally, Articles 26 and 27 of foreign trade law establish the classification of commodities according to tariff codes and the applicability of Mexican Official Standards:

Article 26. In any case, importing, transit and transportation of commodities are subject to the Mexican Official Standards in accordance with the law of the matter. Dispositions of standardization to the import, transportation or transit of commodities different from the Mexican Official Standards will not be in legal agreement. Commodities subject to Mexican Official Standards are identified in terms of tariff codes and the corresponding nomenclature, according to the respective tariff.

The Secretariat will determine the Mexican Official Standards that the customs authorities will enforce at the entry point for the commodities into the country.

Comments: According to the aforementioned articles, foreign trade laws (Ley de Comercio Exterior) are the base of Annex 2.4.1 (NOMs Agreement), according to which the Secretary of Economy Agreement issues general rules and criteria on foreign trade identifying products and applicable normative documents by means of their tariff codes.

Customs Law

Customs Law-article 36, section I, paragraph c), and section II, paragraph b)-establish how regulation compliance and non-tariff restrictions must be verified when commodities enter and exit the country for importing and exporting purposes.

Comments: The compliance certificate issued by product certification organizations is accepted to prove compliance with regulations and non-tariff restrictions. It must be attached to the corresponding shipment declaration.

Federal Consumer Protection Law

The Consumer Affairs Bureau has authority over the matter and, according to this Law:

Article 96. In order to apply and enforce what is stated in this law and in the Federal Law on Metrology and Standardization, if no other agency has authority over the matter, this Agency shall perform the supervision and surveillance needed when products or commodities are managed, stored, transported, distributed, or expended, or for which services are provided, including in transit services.

In order to perform the aforementioned supervision and surveillance, the Agency shall act according to this law and to the procedure terms provided by the Federal Administrative Procedures Law (Ley Federal de Procedimiento Administrativo). Regarding the compliance with Mexican Official Standards, it shall act according to the Federal Law on Metrology and Standardization.

Comments: The Consumer Affairs Bureau (PROFECO – Procuraduría Federal de Consumidor) may perform product surveillance at the point of sale, manufacture, or distribution in order to assure the compliance with Mexican Official Standards as far as the product safety or consumer information is concerned. Such compliance may be proven by a Certificate of Compliance issued by UL or any other accredited certification organization. Regarding consumer information, a dictum or evidence issued by an accredited Surveillance Unit will be needed.

LFMN regulation

Article 50. Compliance with consumer information requirements stated in the Mexican Official Standards is not subject to certification. Importers, producers, manufacturers, traders, or service providers are responsible for having their products comply with the requirements enforced by such standards. … Producers, manufacturers, importers, traders, or service providers may resort to the services of accredited and approved Surveillance Units in order to obtain evidence of compliance or a dictum proving that requirements stated in the Mexican Official Standards on consumer information are complied with. Such documents will be valid before the competent authorities. …

Comments: Regardless of related safety standards, the Mexican Official Standards that apply to consumer information on electric and electronic products are as follows:

NOM-024-SCFI-1998 – Consumer information – Electronic and electrical devices and electrical household appliances – Instructions and warranties for products.

NOMs Agreement

Annex 2.4.1 (NOMs Agreement), according to which the Secretary of Economy issues general rules and criteria on foreign trade, states the following on Article 5:

At the time the commodities listed in articles 1, 2, and 8 of this Agreement enter the national territory, importer must attach to the importing request the original or a copy of the NOM document/certificate issued by the competent agency or accredited certification organizations, which in turn must be approved according to the terms stated in LFMN, or any other document that NOMs explicitly state for the effect of proving such compliance…

Comments: This agreement is a useful tool to determine, according to the tariff code assigned to the product, which Mexican Official Standards must be complied with when the commodities enter the country and during commercialization.

Conformity Assessment Policies and Procedures

LFMN Regulations state the following:

Article 80. Conformity Assessment Policies and Procedures may be generally or specifically applied to each Mexican Official Standard in particular and, when required, to Mexican Standards as well. They may include a description of the requirements that users must comply with, in addition to applicable procedures, technical and administrative considerations, response time, and request forms for applicable documents containing compliance evaluation results.

Article 82. The Secretary shall notify the corresponding parties regarding the conformity assessment procedures issued by agencies and published in the Official Gazette, according to what is stated in international agreements and treaties subscribed to by the United States of Mexico.

Comments: These articles support different schemes offered by UL during product certification procedures, due to the fact that such schemes are based on the same Conformity Assessment Policies and Procedures published in the Official Gazette on October 24, 1997, which were updated by those published between February 29 and May 24, 2000, December 10, 2001, July 4, 2002, and July 27, 2004. These Policies establish general dispositions under which Product Certification Organizations may issue the corresponding certificates, in addition to delivery times, different Certification Schemes, certification requirements, family grouping criteria, and certificate expiration dates.