One of the most recognized authorities for wiring safety is the Underwriters Laboratories (UL), a not-for-profit organization dedicated to establishing and maintaining safety standards across multiple industries. UL for the wiring industry provides a large number of quality inspection services. Services provided include:

　　Included in the UL list. Verify wiring and related hardware safety levels.

　　UL test. According to TIA / EIA cabling standards set out in the performance specifications, test cabling transmission performance and safety level; and through quality assurance monitoring and factory surprise checks, regular inspection.

　　UL communication wiring

　　UL divides cabling used by voice and data systems into "communications cabling and cables," abbreviated CM. This category provides a variety of safety levels for specific applications to verify the quality of the cable jacket, as follows:

　　CMP: Filled level communications cable, which is the highest cable security rating, with perfect flame retardancy and low smoke and toxin emissions. According to the UL definition, a bundle of CMP cables must be self-extinguishing within less than 5 meters of combustion spread under fan intensive combustion conditions. CMP cables use Teflo-based chemicals to stop burning and disperse, minimizing emitted fumes and toxins. This adds significant cost to the lower UL rated cables. CMP-grade cables are used in buildings where cables are routed through ventilation and return air. In the event of a fire, the building will not be filled with large quantities of smoke or dangerous toxins from the cables. The U.S. air bag is widely used in the United States, but less used in other parts of the world. CMP-level cables must undergo a rigorous combustion test: ULArray10- "Flame Propagation Smoke Density Test"

　　CMR: Mainline communications cable. This is the second most rated cable, which has the perfect fire-retarding ability but does not test the emitted smoke toxins. In addition to CMP and cables, CMR cables and all other communications cables use halide-based chemicals, such as chlorine, to prevent combustion and diffusion. By definition, a bundle of CMR cables must be extinguished within less than 5 meters of combustion spread under fan forced combustion conditions. CMR cable jackets are typically made of a type of PVC that emits chlorine gas in the combustion chamber. The chlorine gas depletes the oxygen in the air and extinguishes the flame. CMR grade cables are widely used in trunk applications where the ventilation system is physically separated from the cabling system. This is very common in Asia and Australia. CMR-class cables must undergo intensive flame testing: UL1666- "Cable Flame Propagation Level Test for Vertical Mounting to Middle"

　　CM / CMG: General Communication Cabling. This is common in the building's horizontal alignment, which is usually divided into smaller bundles compared to CMR cables. CM / CMG cables use halogen-based chemicals when grouping. By definition, in a small bundle of cables, the CM / CMG cable must be self-extinguishing within less than 5 meters of its combustion spread. The flame is not forced to use a fan to burn. CM / CMG cable jacket is usually made of a certain type of PVC, in the combustion chamber will emit chlorine. CM / CMG cables are commonly used for horizontal routing in the UK, Asia and Australia. CM / CMG cable must pass CSAFT-4 "vertical combustion test"

　　CMX: Residential Communications Cabling. This type of cable is limited to residential or other small applications where the number of communication cables used is very small, and these applications typically only have one cable laid. CMX-level tools can not be used in bundled cable applications. CMX cable must pass ULVW1 combustion test

　　Low Smoke Zero Halogen (LSZH)

　　Another safety level used in the cabling industry is the Low Smoke Zero Halogen (LSZH) cable. This level of security is divided by the ISO / IEC standard and is widely used in Europe.

　　The LSZH grade, like the ULCMP grade, tests for flame retardancy and emitted gas. As its name implies, the burning LSZH does not emit a halide gas and emits very low levels of smoke. LSZH grade cables can be used for copper and fiber optic communications cables and have a similar structure to UL-rated cables.