A Practical Guide for Manufacturers

Anyone developing or marketing electrical products for the U.S. market will sooner or later come across the term NRTL. NRTL certification is frequently required in quotations from testing laboratories, procurement specifications issued by major industrial customers, and technical product requirements.

At the same time, the NRTL system remains one of the most misunderstood aspects of North American product compliance. Many manufacturers assume that NRTL certification is legally required for all electrical products, that only UL is authorized to certify products for the U.S. market, or that an ETL or CSA certification carries less value than a UL certification. None of these assumptions is correct.

In reality, the NRTL system is a program recognized by the U.S. Occupational Safety and Health Administration (OSHA) to ensure that certain electrical products are evaluated by independent and qualified testing organizations. Although all Nationally Recognized Testing Laboratories (NRTLs) hold the same regulatory status, they differ in their organizational structure, global presence, project turnaround times, and fee structures.

Another aspect that is often underestimated is the total cost of certification. The initial product evaluation represents only part of the overall cost. After certification has been granted, manufacturers typically incur ongoing expenses for factory inspections, annual fees, and technical modifications to certified products. Understanding these factors during the planning phase can help avoid unexpected costs and significantly improve the efficiency of certification projects.

This guide explains:

• What an NRTL is and why the NRTL Program exists
• The role of OSHA within the NRTL system
• When NRTL certification is required
• Which organizations are recognized as NRTLs
• How the certification process works
• The ongoing obligations after certification
• How the total cost of NRTL certification is structured
• The differences between individual NRTLs
• Whether UL actually offers advantages over other NRTLs
• The most common misconceptions manufacturers should be aware of

What is an NRTL?

NRTL stands for Nationally Recognized Testing Laboratory.

These are independent testing organizations that have been officially recognized by the Occupational Safety and Health Administration (OSHA) to test and certify specific types of electrical products in accordance with applicable U.S. safety standards.

These are independent testing organizations that have been officially recognized by the Occupational Safety and Health Administration (OSHA) to test and certify specific types of electrical products in accordance with applicable U.S. safety standards.

An NRTL does not establish its own legal requirements.

Instead, its role is to determine whether a product complies with the applicable safety standards and can be consistently manufactured in accordance with the certified design.

A common misconception is that an NRTL is a government agency.

This is not the case.

NRTLs are privately operated organizations that are recognized by OSHA for specific product categories and safety standards. To obtain and maintain this recognition, they must demonstrate technical competence, independence, and compliance with the requirements of the OSHA NRTL Program.

Recognition is not granted for all product types. Each organization is recognized only for the specific product categories and safety standards for which it has been evaluated and approved by OSHA.

As a result, an NRTL is not authorized to certify every type of product. Its scope is limited to the product categories and standards covered by its OSHA recognition.

Why Does the NRTL Program Exist?

The United States follows a different approach to product safety than many European countries.

While manufacturers in Europe are permitted to declare conformity for many categories of products under their own responsibility, the U.S. occupational safety system requires many types of electrical equipment used in the workplace to be evaluated by an independent and recognized testing organization.

OSHA itself does not perform product testing.

Instead, it operates a recognition program for independent testing organizations. These organizations are responsible for evaluating products and verifying compliance with the applicable safety standards.

This creates a system that combines government oversight with the technical expertise of specialized certification bodies.

For manufacturers, this means that product certification is not issued by OSHA itself, but by an organization that has been officially recognized by OSHA as a Nationally Recognized Testing Laboratory (NRTL).

Is NRTL Certification Legally Required?

This is one of the most frequently asked—and at the same time one of the most misunderstood—questions regarding the U.S. product approval system.

The short answer is:

Not for every product, and not under a single federal law.

Nevertheless, NRTL certification is, in practice, essential for many types of electrical products.

To understand why, it is important to distinguish between the different parties involved.

The Role of OSHA

The Occupational Safety and Health Administration (OSHA) is the U.S. federal agency responsible for workplace safety and health.

Its mission is to ensure safe and healthy working conditions for employees.

However, OSHA does not test products or issue product certifications.

Instead, OSHA requires that certain types of electrical equipment used in the workplace be tested and approved by a Nationally Recognized Testing Laboratory (NRTL).

The actual testing and certification process is therefore carried out by recognized NRTLs—not by OSHA itself.

What Does “Approved Equipment” Mean?

Many OSHA regulations refer to the term “approved” or “approved equipment.”

This does not mean that the equipment has been approved directly by OSHA.

Instead, equipment is generally considered approved when it has been tested and certified by an NRTL that is recognized for the applicable product category.

For this reason, employers, facility operators, and regulatory authorities often require an NRTL certification mark, even though it may not be explicitly referenced in a specific law.

The Role of the AHJ (Authority Having Jurisdiction)

Another important party in the approval process is the Authority Having Jurisdiction (AHJ).

The AHJ is the authority responsible for determining whether a piece of equipment or an installation may be placed into service.

Depending on the application, the AHJ may be:

• The local Electrical Inspector
• The building authority
• The fire marshal or fire department
• A governmental agency
• Any other authority responsible for approving the installation

The AHJ will often verify whether the electrical equipment carries a recognized NRTL certification.

If it does not, the installation or commissioning of the equipment may be rejected—even if the product itself is technically safe.

Insurance Requirements

Many insurance providers also require the use of certified electrical equipment.

If an incident occurs and uncertified equipment is found to have been used, this may affect the settlement of an insurance claim.

For this reason, many facility operators include certified products as part of their internal procurement requirements.

Customer Requirements

In addition to legal and regulatory requirements, customer specifications also play an important role.

Large industrial companies, machine manufacturers, automotive companies, and operators of industrial facilities frequently specify that electrical components must carry a recognized NRTL certification mark.

In these cases, it is often irrelevant whether certification is legally required—the customer’s specification makes it a contractual requirement.

Does Every Product Require NRTL Certification?

No.

Not every electrical product automatically falls within the scope of the NRTL Program.

Whether certification is required depends on several factors, including:

• The type of product
• Its intended application
• The installation environment
• The applicable safety standards
• Customer requirements
• Requirements imposed by the Authority Having Jurisdiction (AHJ)
• State and local regulatory requirements
• The type of product
• Its intended application
• The installation environment
• The applicable safety standards
• Customer requirements
• Requirements imposed by the Authority Having Jurisdiction (AHJ)
• State and local regulations

In particular, for industrial electrical equipment, laboratory instruments, industrial control panels, power supplies, and machine components, NRTL certification is often the simplest and most cost-effective way to achieve market acceptance and avoid delays during installation or commissioning.

Legal Requirement or Business Necessity?

From a manufacturer’s perspective, this distinction is important.

From a strictly legal standpoint, NRTL certification is not explicitly required for every electrical product.

In practice, however, the combined requirements of OSHA, Authorities Having Jurisdiction (AHJs), insurance providers, and end customers often make NRTL certification a de facto prerequisite for successfully marketing electrical products in the United States.

For this reason, many manufacturers view NRTL certification less as a legal obligation and more as an essential component of their U.S. market access strategy.

Which Products Typically Require NRTL Certification?

Not every electrical product is evaluated under the same requirements. The scope of certification depends on the product type, its intended application, and the applicable safety standards.

Product categories that commonly require NRTL certification include:

• Industrial machinery and machine controls
• Industrial control panels
• Laboratory and test equipment
• Power supplies and battery chargers
• Information technology and telecommunications equipment
• Audio, video, and multimedia equipment
• Household appliances
• Lighting products and luminaires
• Medical electrical equipment (where no additional regulatory approval requirements apply)
• Electrical components used in industrial installations

The appropriate certification strategy should always be determined based on the specific product and its intended application.

Which Organizations Are Recognized as NRTLs?

Many manufacturers automatically associate the term NRTL with UL. In reality, however, UL is just one of several organizations that have been recognized by OSHA as a Nationally Recognized Testing Laboratory.

From a regulatory perspective, all recognized NRTLs have the same status. They are authorized to test and certify products within the scope of their OSHA recognition. Consequently, a product bearing an ETL, CSA, or TÜV certification mark is no less valid than a product carrying a UL certification mark, provided the respective organization is recognized for the applicable product category and safety standard.

The differences between NRTLs are therefore less about regulatory recognition and more about experience, market presence, project turnaround times, fee structures, and the range of services they provide.

The Most Well-Known NRTLs

Some of the best-known and most widely used Nationally Recognized Testing Laboratories (NRTLs) include:

Organization	Best-Known Certification Mark	Headquarters
UL Solutions	UL Listed / UL Recognized	United States
Intertek	ETL Listed	United States / United Kingdom
CSA Group	CSA	Canada
TÜV Rheinland	TÜV Rheinland	Germany
TÜV SÜD	TÜV SÜD	Germany
SGS North America	SGS	Switzerland
MET Laboratories	MET Listed	United States
QPS Evaluation Services	QPS	Canada
Eurofins Electrical & Electronic Testing	Eurofins	Luxembourg
FM Approvals	FM Approved	United States

In addition to these organizations, there are several other NRTLs, some of which specialize in specific product categories or safety standards.

The complete list of OSHA-recognized NRTLs is published and regularly updated by OSHA.

Are All NRTLs the Same?

From a regulatory perspective, the answer is:

Yes.

All NRTLs recognized by OSHA must meet the same requirements for independence, technical competence, quality assurance, and testing procedures.

As a result, an ETL certification mark is no less valid from a regulatory standpoint than a UL certification mark.

However, the individual organizations differ significantly in several respects.

Technical Expertise

Many NRTLs have decades of experience in specific industries and product categories.

For example, some organizations have particular expertise in:

• Industrial controls
• Laboratory equipment
• Household appliances
• Lighting products
• Medical devices
• Hazardous (classified) locations
• Industrial machinery

Depending on the type of product, this specialized experience can have a significant impact on the quality of technical support and the overall efficiency of the certification project.

Global Network

International manufacturers often prefer organizations with a global network of laboratories and local offices.

This can provide advantages such as:

• Local testing capabilities
• Factory inspections
• Technical support
• Project management
• International certification programs

Project Turnaround Time

Project timelines can also vary considerably between different NRTLs.

Factors that influence turnaround time include:

• Laboratory workload
• Availability of testing capacity
• Product complexity
• Internal review procedures
• Experience of the engineering team

For this reason, the best-known organization is not necessarily the fastest.

Cost Structure

The cost of NRTL certification consists of much more than laboratory testing alone.

Depending on the organization, differences may exist in:

• Engineering hourly rates
• Certification fees
• Annual administrative fees
• Follow-Up Service fees
• Travel expenses
• Fees for product modifications
• Fees for additional manufacturing locations
• Internal administrative procedures

Over the lifetime of a product, these differences can have a significant impact on the total cost of certification.

Is UL Better Than ETL or CSA?

This is one of the most frequently asked questions in the industry.

The answer is:

It depends on the criteria being considered.

From a Regulatory Perspective

From a regulatory standpoint, there is no difference between recognized NRTLs.

All OSHA-recognized organizations are authorized to evaluate and certify products within the scope of their recognition using the same applicable safety standards.

As a result, an ETL or CSA certification mark carries the same regulatory status as a UL certification mark.

From a Market Perspective

This is where UL Solutions clearly enjoys the highest level of brand recognition.

For decades, purchasers, installers, inspectors, and end users have associated product safety with the UL Certification Mark.

As a result, some industries or customers specifically require a UL certification mark, even though other NRTL certification marks would also be acceptable from a regulatory standpoint.

In these cases, the requirement is typically driven by customer specifications or market expectations rather than by legal requirements.

From a Technical Perspective

All NRTLs evaluate products against the same applicable safety standards.

Regardless of which NRTL is selected, a product must comply with the same technical requirements defined by the applicable standard.

Choosing ETL instead of UL—or any other recognized NRTL—does not reduce the technical requirements that the product must satisfy.

Which Organization Is the Best?

There is no universal answer to this question.

The selection of an NRTL should be based on factors such as:

• Experience with the specific product category
• Project turnaround time
• Initial project costs
• Ongoing certification costs
• Quality of technical support
• International presence
• Proximity to manufacturing facilities
• Customer requirements
• Desired market recognition

For many manufacturers, the best-known organization is not necessarily the most cost-effective or technically suitable choice.

A Common Misconception

A common misconception is that switching from one NRTL to another will automatically reduce certification costs.

In reality, fee structures can differ significantly. While one organization may offer lower initial project costs, higher Follow-Up Service fees, factory inspection costs, or administrative charges over the lifetime of the certification may ultimately result in a higher total cost.

For this reason, manufacturers should not select an NRTL based solely on the initial quotation. Instead, they should consider the total cost of ownership over the entire lifecycle of the certification.

The Certification Process – Step by Step

Many manufacturers assume that an NRTL certification project begins with laboratory testing and ends when the certification mark is issued.

In reality, laboratory testing represents only one part of the overall process. An NRTL certification project consists of numerous technical and administrative steps that begin long before the first test is performed and continue throughout the lifetime of the certification.

Although individual steps may vary depending on the product, the applicable safety standards, and the selected NRTL, the overall process is largely the same across all recognized NRTLs.

1. Project Request

Every certification project begins with a technical evaluation of the product.

To perform this assessment, the NRTL typically requires information such as:

• Product description
• Intended use
• Technical specifications
• Electrical schematics
• Bill of Materials (BOM)
• Mechanical drawings
• User manual
• Photographs or CAD data
• Information on existing certifications, if applicable

Based on this information, the NRTL first determines which safety standards apply to the product.

2. Quotation and Project Definition

Following the initial review, the NRTL prepares a quotation.

This typically includes:

• Applicable safety standards
• Scope of the technical evaluation
• Required testing
• Number of test samples
• Estimated project timeline
• Project costs

Differences between NRTLs may already become apparent at this stage, as not every organization follows the same engineering approach or certification methodology.

3. Construction Review

Before laboratory testing begins, a detailed technical review of the product is typically performed.

This step is known as the Construction Review.

During this review, engineers evaluate aspects such as:

• Electrical safety
• Protection against electric shock
• Insulation systems
• Creepage and clearance distances
• Protective earthing
• Overcurrent protection
• Temperature performance
• Fire hazards
• Plastic materials
• Product markings
• Warning labels
• User instructions

The objective is to identify potential non-conformities before formal testing begins.

A thorough Construction Review can significantly reduce the amount of redesign and retesting required later in the project.

4. Evaluation of Critical Components

An essential part of every NRTL certification project is the evaluation of Critical Components.

These are components that have a direct impact on product safety.

Examples include:

• Power supplies
• Transformers
• Fuses
• Relays
• Power switches
• Cables and wiring
• Connectors
• Cooling fans
• X and Y capacitors
• Optocouplers
• Insulation materials
• Plastic materials
• Power cords

Many of these components already have their own safety certifications.

Consequently, the certification engineer evaluates not only the finished product but also the safety characteristics of the components used within it.

The approved Critical Components become part of the certification documentation and, as a general rule, cannot be replaced without prior approval.

5. Laboratory Testing

Only after the documentation review has been completed does formal safety testing begin.

The required tests depend entirely on the applicable safety standard.

Typical tests may include:

• Dielectric withstand (Hipot) testing
• Protective earth continuity testing
• Leakage current measurements
• Temperature testing
• Overload testing
• Single fault condition testing
• Mechanical strength testing
• Stability testing
• Push and pull force testing
• Flammability testing
• Verification of markings and labeling

Not every product requires all of these tests.

The exact test program depends on the applicable safety standard and the design of the product.

Many changes, however, still require engineering effort and therefore result in additional costs.

Changes to the Certification Report

The Certification Report defines the certified configuration of the product.

If, for example,

• additional models are added,
• technical specifications are updated,
• new options are documented,
• or manufacturing information is revised,

the Certification Report must be updated accordingly.

Even if no additional testing is required, these changes typically involve engineering and administrative fees.

Changes to Critical Components

One of the most common post-certification changes involves the list of approved Critical Components.

Typical examples include:

• A new power supply
• A different transformer
• A new relay
• A different fuse
• A new cooling fan
• A different plastic material
• A different power switch

In these cases, the NRTL must first determine whether the replacement component is considered equivalent or whether additional evidence or testing is required.

Even if no laboratory testing is necessary, engineering work is typically required to evaluate the change and update the certification documentation.

Changes to the Certification

Administrative changes may also result in additional charges.

Examples include:

• A change of company name
• A new company address
• A change of manufacturer
• A change of manufacturing location
• Updates to company contact information

Although these changes usually require little or no technical evaluation, administrative processing fees are commonly applied.

Adding New Products to an Existing Certification File

Many manufacturers assume that every new product automatically increases their annual certification costs.

This is generally not the case.

If a new product can be added to an existing Certification File and belongs to the same product category, the ongoing certification costs generally remain unchanged.

Typically, only one-time costs are incurred for:

• Technical evaluation
• Updating the Certification Report
• Additional testing, if required
• Expanding the certification documentation

The annual fees and Follow-Up Service requirements typically remain unchanged.

The situation may be different if the new product belongs to a different product category. In such cases, an additional Certification File may be required, which can result in additional administrative fees and, depending on the NRTL’s fee structure, additional ongoing costs.

Why Are There Ongoing Costs?

An NRTL certification program does not end with the issuance of the certification.

Throughout the lifetime of the certification, ongoing activities are required, including:

• Regular factory inspections
• Maintenance of certification documentation
• Technical evaluations of product changes
• Updates to Certification Reports
• Administration of certified products
• Maintenance of the Follow-Up Service program

For this reason, manufacturers should not base their choice of an NRTL solely on the initial certification cost. Instead, they should consider the total cost of ownership over the entire lifecycle of the product.

Which Safety Standards Are Applied for NRTL Certification?

A common misconception is that an NRTL evaluates products according to its own safety requirements or that there are specific “NRTL standards.”

Neither is true.

A Nationally Recognized Testing Laboratory (NRTL) does not develop its own legal product requirements. Its role is to evaluate and certify a product’s compliance with the applicable safety standards.

The applicable standard is determined not by the selected NRTL, but by the type of product and its intended use.

Who Develops the Safety Standards?

Safety standards are developed by various standards development organizations.

Some of the most important include:

• UL Standards & Engagement (ULSE) – Develops numerous UL safety standards.
• CSA Group – Develops many North American safety standards.
• ANSI (American National Standards Institute) – Accredits standards development processes and coordinates the U.S. standardization system.
• ASTM International – Develops technical standards for a wide range of industries.
• NFPA (National Fire Protection Association) – Develops, among others, the National Electrical Code (NEC).

An NRTL then evaluates whether a product complies with the requirements of the applicable safety standard.

Are UL Standards Exclusive to UL?

No.

This is probably one of the most common misconceptions about the North American certification system.

Although many safety standards begin with the designation “UL”—such as UL 62368-1, UL 61010-1, or UL 508A—they are not exclusive to UL.

Other OSHA-recognized NRTLs, including Intertek, CSA Group, TÜV Rheinland, and TÜV SÜD, may also evaluate products to these standards, provided they are recognized by OSHA for the applicable scope.

In other words, the standard does not belong to the NRTL performing the certification.

Which Standard Applies to My Product?

Selecting the correct safety standard is one of the most important steps in the entire certification process.

The applicable standard depends on factors such as:

• Product type
• Intended application
• Intended user
• Electrical design
• Product functions
• Applicable installation requirements

A single product may also be subject to multiple safety standards.

Examples of Common Safety Standards

Product	Typical Safety Standard*
Audio, video, and IT equipment	UL/CSA 62368-1
Laboratory and test equipment	UL/CSA 61010-1
Industrial Control Panels	UL 508A
Industrial control equipment	UL 61010-2-201 or UL 508 (depending on the product)
Household appliances	UL/CSA 60335 Series
Luminaires and lighting equipment	UL 1598
Power supplies	Depending on the application, e.g., UL 62368-1 or UL 1310
Medical electrical equipment	AAMI ES60601-1 / CAN/CSA C22.2 No. 60601-1

*The applicable standard always depends on the specific product and its intended application.

A Safety Standard Does Not Replace Technical Evaluation

Many manufacturers initially try to determine the applicable safety standard themselves.

This can be problematic.

Even minor differences in the intended use of a product may result in a different safety standard or additional requirements.

For example, the applicable standard may change if a product:

• Is intended exclusively for industrial use
• May also be used by consumers
• Forms part of a machine
• Is marketed as a standalone product
• Is intended for use in hazardous (classified) locations

For this reason, the final selection of the applicable safety standard is typically made together with the NRTL during the project definition phase.

Can Multiple Standards Apply to the Same Product?

Yes.

Complex products often have to comply with multiple requirements simultaneously.

For example, a product may be subject to:

• A product safety standard
• An installation standard
• Additional industry-specific requirements

In addition, many manufacturers require certifications for multiple markets, such as Europe, Canada, or other international regions. As a result, certification projects often involve multiple standards and regulatory systems in parallel.

International Harmonization

Over the past several years, many North American safety standards have been aligned with, or fully harmonized to, international IEC standards.

Examples include:

• IEC 62368-1 → UL/CSA 62368-1
• IEC 61010-1 → UL/CSA 61010-1
• IEC 60335-1 → UL/CSA 60335-1

As a result, the technical requirements have become increasingly similar.

However, national deviations (National Differences) still exist for the United States and Canada and must be considered during the certification process.

Selecting the Right Standard Saves Time and Cost

Choosing the correct safety standard affects much more than the technical evaluation.

It directly influences:

• The scope of testing
• Project duration
• Overall certification costs

Selecting the wrong standard may require additional testing, repeated evaluations, or project delays.

For this reason, the applicable safety standards should be determined as early as possible based on the product’s actual intended use.

Which NRTL Is the Right Choice?

Once it has been determined that NRTL certification is required, manufacturers are often faced with the next question:

Which NRTL should be selected for the project?

There is no universal answer.

All OSHA-recognized NRTLs have the same regulatory status. However, they differ in their technical expertise, project execution, global presence, and fee structures.

For this reason, selecting an NRTL should not be based solely on the initial quotation.

Selection Criteria

When choosing an NRTL, manufacturers should consider factors such as:

• Experience with the relevant product category
• Availability of the required safety standards
• Project turnaround time
• Technical support
• Global presence
• Proximity to the manufacturing facility
• Ongoing certification fees
• Costs associated with product changes
• Costs for additional manufacturing locations
• Customer requirements

Not every criterion is equally important for every project.

For high-volume products with a long market life, long-term certification costs are often the deciding factor. For products with aggressive time-to-market objectives, turnaround time and laboratory availability may be more important.

Experience with the Product Category

Not every NRTL has the same level of experience across all product categories.

Some organizations have extensive expertise in areas such as:

• Industrial controls
• Laboratory equipment
• Medical devices
• Lighting products
• Household appliances
• Information technology and telecommunications equipment

A high degree of specialization can positively influence both the quality of technical support and the efficiency of the certification project.

Project Turnaround Time

Project timelines can vary considerably between different NRTLs.

Factors that influence turnaround time include:

• Laboratory workload
• Availability of testing capacity
• Duration of technical reviews
• Product complexity
• Availability of the responsible engineers

For products with tight launch schedules, turnaround time can be a decisive factor.

Global Presence

Manufacturers with multiple development or manufacturing locations often benefit from working with an NRTL that has an international network.

Advantages may include:

• Local technical contacts
• Factory inspections
• Technical coordination
• International certification projects

Long-Term Costs

The cost of an NRTL certification project should not be evaluated solely on the basis of the initial quotation.

Equally important are the costs incurred throughout the lifetime of the certification.

These may include:

• Annual Fees
• Follow-Up Services
• Factory Inspections
• Changes to the Certification Report
• Changes to Critical Components
• Additional manufacturing locations
• Additional Certification Files

For products with a long market life, these ongoing costs can represent a significant portion of the total cost of certification.

Customer Requirements

In some industries, customers or end users already specify which certification mark is acceptable.

For example, certain tenders explicitly require a UL Listed certification mark, even though other NRTL certification marks would also be acceptable from a regulatory standpoint.

In such cases, manufacturers should verify at the beginning of the project whether a particular certification body is required by contract or by market expectations.

Is There a “Best” NRTL?

No.

The best NRTL always depends on the specific project.

A manufacturer of laboratory equipment may reach a different conclusion than a manufacturer of lighting products or industrial control equipment.

For this reason, the selection should always be based on the technical requirements, commercial considerations, and the expectations of the target market.

Selection Criteria at a Glance

Criterion	Why It Matters
Experience with the product category	Can significantly influence project execution and the quality of technical support.
Project turnaround time	Important for products with aggressive time-to-market objectives.
Global presence	Beneficial for manufacturers with multiple development or manufacturing locations.
Ongoing fees	Affect the total cost of certification throughout the product lifecycle.
Change management	Particularly relevant for products that undergo frequent design changes.
Customer requirements	Some customers accept or prefer specific certification marks.
Long-term partnership	Using the same certification partner for multiple products can simplify future certification projects.

The Right Choice Is Rarely the Cheapest

A low initial quotation does not necessarily represent the most cost-effective solution.

Likewise, the best-known NRTL is not automatically the best choice for every project.

The decision should be based on an overall evaluation that considers not only the technical requirements, but also the long-term certification costs and the level of support required throughout the product’s lifecycle.

A well-selected certification partner can not only accelerate market entry but also reduce the effort associated with future product modifications and certification updates.

UL or ETL – Is There Really a Difference?

Few topics generate as much discussion in connection with NRTL certification as the question:

“Do we need a UL certification mark, or is ETL sufficient?”

Many manufacturers believe that UL is the only organization authorized to certify products for the U.S. market, or that an ETL certification mark carries less value than a UL certification mark.

Neither assumption is correct.

From a regulatory standpoint, both UL Solutions and Intertek (ETL) are recognized by OSHA as Nationally Recognized Testing Laboratories (NRTLs). Both organizations are authorized to test and certify products within the scope of their OSHA recognition using the same applicable safety standards.

Nevertheless, there are differences that manufacturers should consider when selecting an NRTL.

Regulatory Recognition

From OSHA’s perspective, there is no fundamental difference between UL and ETL.

Both organizations are recognized as NRTLs and are authorized to certify products within the scope of their recognition.

Consequently, a product bearing an ETL Listed certification mark meets the same regulatory requirements as a product bearing a UL Listed certification mark.

What matters is not the certification mark itself, but whether the product has been certified by an NRTL recognized for the applicable product category.

Are the Same Safety Standards Applied?

Yes.

Another common misconception is that UL certifies products exclusively to UL standards, while ETL applies different requirements.

In reality, both organizations evaluate products against the same North American safety standards.

Whether a product is certified to UL 62368-1, UL 61010-1, or UL 508A depends on the product category—not on the NRTL performing the certification.

As a result, the technical requirements remain the same regardless of the selected NRTL.

Market Acceptance

This is where the greatest difference exists.

The UL Certification Mark enjoys exceptional recognition throughout North America. For decades, it has been closely associated with product safety and is widely recognized by manufacturers, installers, regulatory authorities, and end users.

This does not mean that other NRTL certification marks are less acceptable from a regulatory standpoint.

However, some customers, facility operators, or procurement specifications explicitly require a UL certification mark. In most cases, these requirements are based on internal company policies or long-standing industry practices rather than legal obligations.

Manufacturers should therefore verify at an early stage whether their customer requires a specific certification mark.

Technical Quality

It is often assumed that UL performs more rigorous testing than ETL.

There is no general basis for this assumption.

Both organizations evaluate products against the same applicable safety standards and must comply with the requirements of the OSHA NRTL Program.

Differences may arise in the practical execution of a project, for example due to:

• The experience of the assigned certification engineer
• Internal review procedures
• Interpretation of specific standard requirements
• Communication during the certification project

These differences generally depend on the specific project and the engineering team involved—not on the certification mark itself.

Project Turnaround Time

Turnaround time is not an inherent characteristic of any particular NRTL.

It depends on factors such as:

• Laboratory workload
• Product complexity
• Availability of testing capacity
• Quality of the submitted documentation
• The speed with which the manufacturer responds to technical questions

For this reason, it is not possible to make a general statement such as “UL is slower” or “ETL is faster.”

Costs

There is also no universal answer when it comes to costs.

Depending on the project, differences may exist in:

• Engineering effort
• Laboratory testing costs
• Annual Fees
• Follow-Up Service fees
• Costs associated with product modifications
• Fees for additional manufacturing locations
• Administrative charges

A lower quotation for the initial certification project does not necessarily result in lower total costs over the lifetime of the product.

When Does UL Make More Sense?

UL may be the preferred choice when:

• A customer explicitly requires a UL certification mark
• The product is marketed in an industry where the UL brand carries significant recognition
• The UL mark provides marketing or commercial value
• Existing products are already certified by UL and the manufacturer wishes to maintain a consistent certification strategy

When Might ETL or Another NRTL Be the Better Choice?

Another NRTL may be an equally suitable—or even more cost-effective—solution when:

• There are no customer requirements for a specific certification mark
• Comparable technical expertise is available
• Shorter project turnaround times can be achieved
• Long-term certification costs are lower
• A strong working relationship already exists with the selected NRTL

Conclusion

From a regulatory perspective, UL and ETL are equivalent. Both are recognized by OSHA as Nationally Recognized Testing Laboratories (NRTLs) and are authorized to certify products within the scope of their recognition using the same applicable safety standards.

For this reason, the selection of an NRTL should not be based on the assumption that one certification mark is technically or legally superior to another.

Instead, manufacturers should ask themselves the following questions:

• Does my customer require a specific certification mark?
• Which organization has the greatest experience with my product category?
• What are the long-term certification costs?
• How important are international presence and local technical support?
• Which certification partner best supports my company’s long-term market access strategy?

How ScopeRight Supports Manufacturers

Selecting the right NRTL, the appropriate safety standards, and an efficient certification strategy is often more complex than it first appears. Numerous technical and regulatory decisions must be made during the early stages of product development, and these decisions can have a direct impact on project timelines, certification costs, and market access.

ScopeRight helps manufacturers make these decisions early in the product development process. Our platform assists in identifying the applicable Safety, EMC, RF, and regulatory requirements for a product while supporting the planning of both national and international certification projects. Before engaging a testing laboratory, manufacturers can determine the expected testing scope, identify the applicable standards, and estimate the overall certification effort.

Our expertise extends beyond software. The founders of ScopeRight have many years of experience in international product compliance and spent many years working for a globally recognized Nationally Recognized Testing Laboratory (NRTL). This experience includes the technical evaluation of products as well as the practical management and execution of national and international certification projects.

As a result, we understand not only the requirements of the applicable safety standards, but also the internal processes of testing laboratories, the typical challenges encountered during certification projects, and the factors that have the greatest impact on project timelines and certification costs.

Our goal is not to replace NRTLs or testing laboratories. On the contrary, they remain an essential part of the certification process. Instead, we help manufacturers make informed technical and regulatory decisions before a certification project begins. Careful planning at an early stage can help avoid unnecessary testing, reduce project delays, and minimize avoidable certification costs.

Whether selecting the appropriate safety standards, preparing for an NRTL certification, or developing an international market access strategy, ScopeRight combines specialized compliance software with extensive practical experience to help manufacturers bring products to international markets more efficiently and successfully.