CL3 is the abbreviation for Class 3 Cable, a type of low-voltage wiring rated for power-limited circuits that carry up to 300 volts. These cables are designed for use in commercial and industrial environments where higher voltage or power capacity is required compared to Class 2 circuits, while still maintaining compliance with safety and fire performance standards.
Class 3 (CL3) cables are part of the National Electrical Code’s (NEC) classification system for power-limited circuit wiring. Unlike Class 2 (CL2) cables, which are rated for circuits up to 150 volts, CL3 cables are engineered to handle up to 300 volts, making them suitable for more demanding applications such as high-powered control systems, intercom networks, public address systems, and large-scale audiovisual installations.
The “Class 3” designation indicates that the cable is intended for use in power-limited systems where safety is ensured by current and voltage restrictions defined in NEC Article 725. CL3 cables feature insulation and jacketing materials designed to prevent fire propagation and electrical hazards, and they must meet flame and smoke performance criteria as outlined by Underwriters Laboratories (UL) testing standards. Variants such as CL3R (Class 3 Riser Cable) and CL3P (Class 3 Plenum Cable) extend this classification to riser and plenum applications, respectively, providing flexibility across multiple building environments.
Commonly regulated under the National Electrical Code (NEC), specifically Article 725, which governs power-limited circuits for both Class 2 and Class 3 systems. Underwriters Laboratories (UL) provides certification and testing standards for CL3 cables, including UL 13, which establishes requirements for power-limited circuit cables.
The CL3 classification was introduced as part of the NEC’s effort to standardize safety ratings for power-limited circuit wiring in multi-use facilities. As technology in communication, security, and control systems advanced, the demand for cables capable of carrying higher voltages while maintaining low fire and shock risk led to the creation of the Class 3 category. This allowed engineers and facility designers to distinguish between cable types based on both voltage capacity and environmental requirements, improving compliance and performance in complex commercial infrastructure.
Their versatility and safety certification make CL3 cables a preferred choice for environments where system reliability, performance, and fire safety are equally critical.