American standard MC cable do not have a 2-hour fire rating.
The certification and specifications of American standard MC cable mainly focus on their safety performance and scope of application, rather than specific fire rating times. Although metal clad cables meet specific UL certifications, which ensure their standards in safety, electrical performance, and other aspects, these certifications are not directly associated with specific fire rating times, such as a 2-hour fire rating.
Level 5 fire rating for certified cables in the United States:
1. Boost level: These include CMP copper cables (UTP and SCTP) and OFNP or OFCP fiber optic cables, which are the highest level of cables. When the fan blows in, the flame on the cable will extinguish on its own within a range of 5 meters. Due to the presence of chemicals in cables, they do not release toxic gases or vapors during combustion or at extremely high temperatures.
2. Trunk level: The second level cable includes CMR copper cable, OFNR or OFCR fiber optic cable. The requirement is that the bundled cables should extinguish the flame within 5 meters when blown by a fan.
3. Commercial grade: This includes CM copper wire and OFN or OFC fiber optic cables. Commercial grade cables are lower than the backbone grade, and flames on bundled cables must be extinguished within a range of 5 meters without mandatory fan restrictions or smoke or toxicity regulations. Commercial grade cables are typically used for horizontal wiring and are often bundled together.
The determination of the American standard fire rating is usually based on more specific testing standards, such as the UL1581 series standards, which specify the testing methods and requirements for the flame retardant performance of a single cable under vertical conditions, including the evaluation of indicators such as combustion time, propagation distance, and residue drop. These tests and
evaluations are conducted to ensure that cables can delay flame spread under specific conditions, thereby reducing the risk of fire hazards
Therefore, the fire resistance of American standard metal clad cable is mainly reflected by meeting specific flame retardant standards, rather than being measured by specific fire rating times.
