Chapter 3 of NFPA 731 and Article 100 of NFPA 70 (NEC) contain official definitions used in both publications. It is important to understand the terms “Labeled” and “Listed” in Chapter 3 of NFPA 731 and Article 100 of the NEC.

Many products are required by codes and standards to be listed by a Nationally Recognized Testing Laboratory (NRTL) such as UL (Underwriters Laboratories). The NRTL’s test and certify products to ensure safety and compliance with the testing standards.

Once products are listed (also called certified), they are then labeled with a mark that shows proof of the product certification or listing.

Below is a sample of NFPA 731. See the actual NFPA 731 text at NFPA.ORG. for complete code sections. Once there, click on their link to free access to the latest edition of NFPA 731.

3.2.3 Labeled. Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

3.2.4 Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.

Below is a sample of the NEC^®. See the actual NEC^® text at NFPA.ORG for complete code sections. Once there, click on their link to free access to the latest edition of NFPA 70.

Article 100 Definitions

Labeled. Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.