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Adaptive Display's Digital Signage Blog

Electrical Safety Certification Marks For Digital Signage

Posted by Adaptive Micro Systems on Tue, Sep 01, 2015


Digital LED signage is a fast-growing market. Customers demand products that are superior in quality and safety. It is critical for manufacturers and retailers to adhere to legal requirements and acquire product certification to ensure safety. A third-party certificate ensures that a product meets the standard requirements.

Since there are several electrical safety certification marks and compliance requirements, it can be confusing to new sign dealers and users. Some of the most commonly asked questions are:

  • What is the acceptable Certified Mark for UL Compliance?
  • What is NRTL and what doe this code requires?
  • What is the difference between UL, CSA, and ETL, and other Listed Marks?

So, here's some quick information.

National Electrical Code NFPA 70

The National Electrical Code (NEC) as been adopted in all 50 states. It serves as the benchmark for safe electrical design, installation, and inspection to protect people and property from electrical hazards.

In NEC, the requirements are referred to “listed” or “labelled” devices.

NEC addresses "the installation of electrical conductors, equipment, and raceways; signalling and communications conductors, equipment, and raceways; and optical fiber cables and raceways in commercial, residential, and industrial occupancies."  (Source:

Nationally Recognized Testing Laboratory

Nationally Recognized Testing Laboratory (NRTL) is an independent laboratory designated by the Occupational Safety and Health Administration (OSHA). It mnitors private sector organizations so that they conduct certification for products to ensure compliance with OSHA electrical and product safety standards.

Each NRTL makes use of a unique, registered certification mark to designate product conformance to safety test standards. After certification, the NRTL gives authorization to the manufacturer to apply for a registered certification mark. Certification and testing done under NRTL receives a NRTL certified mark. This assures that the product complies with the requirements set by one or more required product safety test standards.

It provides independent testing, evaluation and certification of electrically, gas or oil-fired operated product.

OSHA requires organizations to develop products that meet safety standards such as:

  • ANSI: American National Standards Institute
  • ASTM: American Society for Testing and Materials
  • UL: Underwriters Laboratories Inc.
  • CSA: Canadian Standards Association

Occupational Safety and Health Administration (OSHA) Act of 1970

In the Code of Federal Regulations, Paragraph 1910.303 (Subpart S), it is a requirement that electrical equipments should be examined to ensure that it is free of hazards and is suitable for installation.

What do Certification Marks mean?

Certification marks are stamps of approval. It means that the products adhere to rigorous standards for electrical safety and electromagnetic emissions. It also ensures that the products comply with safety laws and are of good quality.

Products with certification marks also mean that it is listed in a public directory maintained by the certifying body.  The product is then subject to an on-going follow-up program - a program which aims to verify and ensure the product's continued compliance over time.

What's the difference between UL and ETL Listed Marks?

Both UL and ETL marks indicate that the product has met the required safety standards and validate that the product has continued to be compliant through follow-up inspections. The only differences are the partnership between the manufacturer and the test lab and their level of involvement.

UL Listed Mark: This is the most common product mark seen on appliances, computer equipment, fire extinguishers and electrical panel boards. Products with a UL mark meet the requirements based on UL's own published Standards for Safety.

ETL Listed Mark:  This mark is proof that the product has been independently tested and meets the applicable published standard. Authorities Having Jurisdiction (AHJs) across the US accept this mark as proof of product compliance.

Ensuring Safety through Product Compliance

LED sign manufacturers and dealers should be sure that their displays have proof of compliance to a certified safety mark. Certified digital signage products must bear the certification mark on the seal or label or to the exterior surface of the sign. LED signage that is certified safe to install and operate ensures the safety of the users and everyone in the community.



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