UL certification of cable

What is UL certification?

UL certification was founded by the global testing and certification organization and standard development organization UL Co., Ltd. of the United States. Since its establishment in 1894, UL has issued nearly 1,800 safety, quality, and sustainability standards, of which more than 70% have become American national standards, and UL is also the Canadian national standard development agency.

The UL fire rating is divided into 5 categories:

  • Pressurized grade. This includes CMP copper cables (UTP and ScTP) and OFNP or OFCP fiber optic cables, which are the highest grade cables. On a bundle of pressurized cables, when a fan is forced to blow to the flame, the flame spread on the cable It will extinguish itself within 5m. And because this kind of cable contains chemical substances, it will not emit toxic smoke or steam when it is burned or at extreme high temperatures. In the United States, supercharged cables are the preferred cable. In communication wiring, It is usually installed in the air return pressurization system used in ventilation ducts or air handling equipment.
  • Trunk level. This includes CMR copper cables and OFNR or OFCR optical fiber cables, which is the second-ranked cable. Bundles of trunk level cables must be extinguished by themselves when the fan is forced to blow the flame on the cable. However, it has no smoke or toxicity specifications. Countries outside the U.S. usually use cables of this fire rating in building trunks and horizontal cables.
  • Commercial grade. This includes CM copper cables and OFN or OFC optical fiber cables. Commercial grade cables are lower than the trunk grade. The flames on the bundled cables must be extinguished by themselves if they spread to less than 5m, but there is no restriction on forced air blowing by fans. There are also no smoke or toxicity specifications. Commercial grade cables are often used for horizontal wiring and are generally bundled together.
  • General-purpose grade. This includes CMG copper cables and OFNG or OFCG optical fiber cables. This grade of cable performance is similar to commercial grade.
  • Household grade. This refers to CMX copper cables. There is no fiber optic classification. It is the lowest level in the UL fire rating. The flame on a household grade cable must be extinguished by itself when it spreads to less than 5m, but there is no smoke or toxicity specification. Class cables are generally only used in home or small office systems where each cable is laid separately. It should not be laid in bundles, because the flame spread of bundled cables is very different from that of a single cable.


In order to ensure data security, people hope that after a fire, there will be enough time to return all data before the entire network goes down, and move them to a safe place to minimize the possibility of data loss. Therefore, in the cable standard, there is another type of fire protection standard, which is called the "line integrity" standard. Its goal is that the cable can still keep the circuit integrity in the fire scene, so that the power and information can still be transmitted normally. Therefore, cables that meet the requirements of series integrity are also called fire-resistant cables.

At present, there are two types of common fire-resistant cable levels:

Standard cable

Chinese standard: at 750℃, it can still work for 90 minutes (E90).

German standard: at 800-850℃, it can still continue to work for 180 minutes (FE180).

Although the latest Chinese data center standard requires all cables to use CMP-level integrated cable, that is, they can transmit data normally without being damaged at a temperature of 500°C, leaving a certain amount of time for emergency backup of information. However, it cannot meet the requirements for fire-resistant cables in the national standards, and it cannot be called a fire-resistant cable.

Scope of application

Mainly used in emergency lighting, fire detection, signal induction sensor, blower system, communication system, equipment control system, fire water pump and fire alarm system circuit cable.

Product features (UL1424 fire alarm line as an example)

  • Lightweight, easy to install, wiring and small footprint;
  • Using high-flame retardant insulating materials, filling materials and sheaths, the cable has strong self-extinguishing properties;
  • Using the sheath to make it easy for cable installation and stripping;
  • The conductor uses solid or multi-strand copper conductors;
  • The cable adopts high flame retardant UL105℃ polyvinyl chloride insulation extrusion;
  • The cable can be added with mica tape or fire-resistant tape to burn the package, and the product structure design can be customized according to the requirements;
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