UL 1425:2022 PDF Download

The UL 1425:2022 standard sets out the requirements for the construction, testing, and marking of electrical and electrical/optical-fiber cables. These cables are specifically designed for non-power-limited circuits in fire-alarm systems, with a voltage rating of 150 volts and lower. The standard applies to cables used in buildings as specified in Article 760 and other relevant sections of the National Electrical Code (NEC), NFPA 70.

The standard describes three types of cables covered by its requirements: Type NPLFP, for installation in "other spaces used for environmental air"; Type NPLFR, for vertical runs in a shaft or runs that penetrate more than one floor; and Type NPLF, for general-purpose fire-alarm use in buildings (excluding use as plenum or riser cable).

The cables covered by the UL 1425 standard consist of two or more insulated circuit conductors, with or without insulated or bare equipment-grounding conductors. Each insulated circuit and grounding conductor is rated for 600 volts. These cables do not include coaxial members and are marked with a voltage rating of 150 volts.

The standard also specifies various construction features for the cables, such as armored cables with interlocked metal strip or metal sheath, cables for encasement in construction materials, and cables for direct burial in the earth. It further addresses the marking requirements for temperature rating, electromagnetic shielding, sunlight resistance, and direct burial capability. Additionally, the presence of optical-fiber members in a cable is indicated by the "OF" designation in the marking.

It's important to note that this standard does not cover cables that contain only optical fibers, which are addressed in the UL 1651 standard. It also excludes cables for electric-light, power, control, Class 1, Class 2, or Class 3 circuits, as well as power-limited fire-alarm circuits covered by the UL 1424 standard.

Lastly, the UL 1425 standard includes specific smoke and flame tests for the different cable types. Plenum cables (Type NPLFP) are tested for smoke and flame characteristics, riser cables (Type NPLFR) are tested for flame propagation height, and general-purpose cables (Type NPLF) can comply with one of two alternative vertical-tray flame tests. Compliance with these tests ensures that the cables meet the necessary safety requirements for their intended use in fire-alarm systems.