Electrical FAQs: What Is NRTL Approval? The NRTL Mark? NRTL Compliance?

A NRTL (pronounced “nurtle”) is a Nationally Recognized Testing Laboratory accredited by the Occupational Safety and Health Administration (OSHA) as an approved certifier of specific industry standards. OSHA accreditation as a NRTL guarantees that an organization meets the requirements of 29 CFR 1910.7. Each NRTL is accredited by OSHA for a particular scope of test standards and has its own unique registered certification mark, which a manufacturer is authorized to place on a certified product. (See more below on the NRTL mark.

If a manufacturer plans to sell or distribute electrical equipment in the United States, it must show their product is safe. This is done by obtaining certification through an OSHA-approved Nationally Recognized Testing Laboratory.

The NRTL can test the given electrical product to a specific national standard, which demonstrates that the product complies with the requirements to sell within the United States. Once approved, the NRTL authorizes the manufacturer to apply the NRTL mark to all future factory production. The only difference between the various NRTL marks lies in the services of the testing laboratories behind them.

There are generally six steps involved in NRTL approval:

1. Preliminary investigation: A NRTL may provide design-stage services to educate a manufacturer on the requirements of standards applicable to their product types.
2. Documentation: Technical documentation will need to be submitted for review by the NRTL, including items such as critical component lists, technical data sheets, component certification details and diagrams.
3. Performance testing: Once all documentation has been approved, the NRTL will conduct performance testing to verify that products meet the standard requirements.
4. Initial auditing: Each manufacturing location will undergo an educational audit to confirm that they are able to manufacture products that conform to the standards.
5. Certification: Once approved, the NRTL will register the product publicly as being certified, and the manufacturer is authorized to apply the NRTL mark.
6. Periodic auditing: OSHA requires periodic auditing of manufacturing sites by NRTL personnel to ensure continued compliance with the standards.

Manufacturers will sometimes state that they are “in compliance with” a standard rather than being officially certified. (In many cases, the term “in compliance with” may be used by a manufacturer when self-declaring that a product conforms to a particular standard.) However, in these cases, most likely the product has not been evaluated or tested by a NRTL. It is always best to confirm certification via the NRTL’s specific certification mark and its official online listings. (For example, ee NSF’s electrical safety listings.)

Once a product is approved, the NRTL authorizes the manufacturer to place a registered certification mark on new factory production units, thereby confirming compliance with the noted electrical standards. Additionally, the NRTL will include the product as certified to the applicable standards in their official online listings. Together, the mark and the official online listing are the primary reference authority for any end user or regulator wishing to verify the certification status of a product.

There is no one NTRL mark.

The NRTL certification mark is unique to the individual NRTL. For example, NSF’s NRTL mark will appear as shown below, while other NRTL marks will be different in appearance.

Certified for the United States only.	Certified for Canada only.	Certified for Canada and the United States.