Underwriters Laboratories

It is a technical regulation (of mandatory compliance) issued by competent agencies through their respective national consultative standards committee, according to what is stated in Federal Law on Metrology and Standardization (LFMN - Ley Federal sobre Metrología y Normalización), Article 40.

NOMs enforce minimum safety requirements that must be complied with by products, processes, facilities, systems, activities, services, production and operation methods, terminology, symbology, packaging, marks, or consumer information

A standard created by a national standards organization or, in its absence, governmental branches according to the Federal Law on Metrology and Standardization (LFMN - Ley Federal Sobre metrología y Normalización), Article 54. An NMX provides common and recurring rules, specifications, attributes, test methods, guidelines, features, or directives applied to products, processes, facilities, systems, activities, services, production/operation methods, terminology, symbology, packaging, marks, or consumer information.

It is intended to help improve processes, products or services according to the specific requirements of manufacturers and consumers who have special needs. These are not mandatory and establish minimum safety and operation requirements for products, processes and services.

Mandatory compliance only applies when:

• The interested party states, by means of certification marks, that their products, processes or services comply with the respective requirements.
• NOM Standard demands the enforcement of and compliance with an NMX in particular.
• Products, goods or services that have been acquired, rented or hired by federal public administration agencies or organizations must comply with the corresponding standard.

An NOM Standard is a mandatory compliance standard (technical regulation) and an NMX Standard is a voluntary compliance standard. However, an NOM may demand NMX compliance if such NOM states that a product must be evaluated by the scope of a specified NMX. Another important difference is that NOMs only apply to product minimum safety requirements, while NMXs include operational requirements as well.

Upon being issued by a governmental branch, NOM standards may be obtained, free of charge, according to the Official Mexican Standards catalog published by the Secretary of Economy or on the Website of the corresponding issuing organization.

In general, NMXs are not free of charge and  a request must be submitted to the issuing standardization organization. However, a Mexican Standards catalog published by the Secretary of Economy lists the titles of each NMX standard.

Having a certificate of compliance with NOM is mandatory for some products at the moment they are imported into Mexico. This is established by the tariff code applied to the product (please refer to the question regarding harmonized tariff codes).

Yes. As a third-party product certification organization, UL issues NOM and/or NMX certificates according to the standards and certification schemes for which we are accredited. (Please visit the PCO Services section)

Mexican laws state that only companies located in Mexican territory, or in a country with which Mexico has signed a free trade agreement or treaty can obtain an NOM certificate. (Please refer to the question regarding legal representatives.)

Yes. The Mexican legal frame states that manufacturers who own a certificate may grant its ownership extension to one or more distributors, traders or importers as long as the certificate has been issued under Scheme I. (For more information, please visit the Certification Schemes section.)

In order to obtain such ownership, both parties must submit the corresponding documentation to UL de México.

It is important that foreign manufacturers (certificate owners*) understand, that upon entering the country, the importer will be requested to show the corresponding personalized certificate. In other words, the certificate to be presented must include the name of the importing company.

* Please refer to the question above regarding companies that can obtain a NOM certificate and the question regarding foreign legal representatives.

The product certification process is governed and established by the Federal Law on Metrology and Standardization (LFMN - Ley Federal sobre Metrología y Normalización) and related regulations, Conformity Assessment Policies and Procedures including general certification criteria approved by the General Directorate for Standards as well as applicable international agreements and guidelines. (Go to Legal Frame.)

Harmonized tariff codes are used as a determining parameter to identify applicable technical regulations (NOMs) required when a product enters the country according to the "Secretary of Economy Agreement to Issue General Rules and Criteria on Foreign Trade (NOMs Agreement,)" published in the Official Gazette on July 6, 2007.

On the other hand, the Industry and Commerce Assistant Secretariat through the Foreign Trade Head Office and the Competitiveness and Standardization Assistant Secretariat through the Norms Head Office (Dirección General de Normas) requested at all Mexican certifications organizations that  from May 1st, 2009 the issued certificates of compliance in accordance with the Mexican Official Standards (NOM) must include the harmonized tariff code corresponding to the respective product . In case the tariff can not be provided to UL de México, the certificate of NOM compliance -will not be issued.

* Please refer to the question below regarding to if UL can determine a tariff code for a product in particular.  

Even though Mexican standards are based on international standards, international compliance certificates are only valid through a mutual recognition agreement between accredited certification organizations. At the moment, certificates issued by other international organizations are not valid in Mexico.

However, if you have reports or test results issued by an international laboratory, you may visit the Secretary of Economy Web site and check whether these documents can be validated through a mutual recognition agreement between laboratories or between certification organizations and laboratories. This is not part of the product certification process and is only possible if normative document requirements are identical, equivalent or modified and the respective tests are performed to fulfill national requirements. According to Federal Law on Metrology and Standardization (LFMN - Ley Federal sobre Metrología y Normalización,) regulations and guideline ISO/IEC 21-1:2005, "identical" means that the standard (NOM or NMX) has technical contents, structures and texts that are identical to regional or international standards or the respective translations present only minimum editorial changes. "Equivalent" and "modified" are understood when part of the standard contents (NOM or NMX) are identical to the regional or international standard, but contents present national adaptations or alternate requirements.

Such agreements must be approved by competent agencies that is available at the Secretary of Economy Web site, under the agreements section.

No. UL does not determine or suggest a tariff code attributed to a product. According to the Mexican Customs Law (Article 54, first paragraph), customs agents are responsible for classifying merchandise at the customs check point.

Yes. If the requesting company is located in a country with which Mexico has signed a free trade agreement or treaty and the legal representative is legally domiciled in one of these countries.

If the requesting company is located in a country with which Mexico has not signed a free trade agreement or treaty, the company must have a legal representative based in Mexico.

It is a group of products that shares the same type and category (new, rebuilt, used, second-hand, second line, discontinued, or non-compliant), and despite different aesthetical features or appearance, has the same design characteristics that assure compliance with the corresponding NOM, according to criteria stated by the Conformity Assessment Policies and Procedures (Políticas y Procedimientos para la Evaluación de la Conformidad) or Approved General Criterion for Certification Activities (Criterios generales en materia de certificación aprobados por la dependencia competente). Note: These criteria are not available on the Internet. You may request a copy from the issuing organization or the Secretary of Economy directly through the General Directorate for Standards. You may download the "Family Grouping Criteria" that applies to the product being certified (identified by standard) in the required documents section found at the PCO Services page.

The representative model will be selected according to the following:

• Established family grouping criteria.
• Models that present more variations, electric components, or types of material.
• Number of allowed models per family product group

UL personnel will address any concerns regarding how to group products into a family and select those that predominantly represent the category and must be submitted to laboratory testing. Otherwise, clients can request that we create a family grouping as an additional service. In such case, submit a free-form request and the required technical information so that we can analyze the product.

Test result reports will only be accepted when issued by laboratories subcontracted by UL, which must be certified by the Mexican Accreditation Entity, A.C. (ema-Entidad Mexicana de Acreditación) and approved by the competent agency as stated in Federal Law on Measurement and Standardization (LFMN - Ley Federal sobre Metrología y Normalización.) Please check the List of Subcontracted Laboratories.

Keep in mind that if a product has been or will be evaluated by a laboratory in a foreign territory, this laboratory must have a mutual recognition agreement with a peer certified and approved in Mexico that performs the corresponding nationally focused tests. (Please refer to the question regarding certificates of compliance with international standards.)

A list of laboratories that have signed such agreements can be found on the Secretary of Economy Website, under the agreements section. There you will find the agreements that were specifically signed by UL in 2000 and extended in 2003. For more information about the latest updates or new MRA's please contact us directly.

NOM marks can only be used when a product compiles with an Official Mexican Standard. Additionally, product labels or marks (and their accessories) must comply with product marking requirements stated in the applicable product standards and the NOM-008-SCFI-1993, "General System of Measurement Units."

It is crucial that data presenting decimal values use a comma, not a dot (for example: 25,5 V instead of 25.5 V.) Additionally, electric and electronic products must comply with consumer information standards NOM-024-SCFI-1998, "Commercial Information for Packaging, Instruction Guides, and Warranties for Electronic, Electrical and Household Appliances," as long as the applicable product safety standard does not regulate the corresponding consumer information. Otherwise, the corresponding product standard item must be complied with if it regulated such product.

Product certification marks must correspond to UL Marks approved and evaluated during the certification process according to the Mark Usage Manual provided when the certificate is first issued. If changes are made to the Mark, UL must be notified in writing.

In all cases, two original copies of the "certification services application" and the original copy or in electronic format of the general and specific technical documentation must be submitted depending on the Scheme under which the product will be certified. A list of general and specific technical documentation can be found in the "required documentation" section of PCO Services.

If this is a first-time application, you must also submit the legal documents requested on PCO Services page. The application form is available for download in our PCO Services page, in the "required documentation" section, or at our offices. Please contact us directly for a service agreement and it will be sent to you.

The application will only be accepted if the required documents are properly completed. Response time for compliance evaluation processes is seven business days for new products or 20 business days for remaining categories from the following business day after the application is received and, if applicable, after detected deficiencies have been corrected.

The original application as well as attached documents will be assigned a reference number so that the applicant can follow up on the certification or dictum process. Copies of the application form will be sealed by UL and returned to the applicant.

When renewing a certificate, you must additionally submit the following:

• A free-form written letter requesting the renewal and stating that the products included in the certificate as well as the information provided for certification purposes have not been changed in any way.
• Test report of the product sampled or product compliance notice provided by UL.

If you request a renewal with changes to the scope, you must submit the applicable additional technical information described in the "required documentation" section of PCO Services.

If the application form and/or service agreement have been altered, they will not be accepted. Application receipt does not guarantee that the corresponding certificate or dictum will be issued as for it depends on resolving the compliance evaluation analysis.

The standard voltage in Mexico is 127 V of alternate current. In case of double or triple phase items, 120/240 V, 220Y/127 V, 480Y/277 V, and 480 V are preferred values.

According to Article 18, Section II of the Electricity Public Services Law, high-, medium-, or low-tension tolerance cannot exceed ten percent (± 10%).