SYSTON 18/4 Plenum-Rated Shielded Control Cable - CMP CL3P

In this review the SYSTON 18/4 plenum-rated control cable is evaluated as a practical choice for professionals and DIYers who need a reliable, low-voltage multi-conductor cable for fire alarm, security, and communication circuits. The single biggest reason to buy is its combination of stranded pure copper conductors with aluminum foil shielding and a CMP flame-retardant jacket, which together deliver durable conductivity and protection against electromagnetic interference in sensitive installations. For anyone installing wiring in ceiling plenums or running low-voltage control lines near other electrical systems, this cable is designed to meet those needs.

Key Features

• Plenum-Rated CMP/CL3P: The CMP flame retardant jacket is suitable for plenum air spaces and provides a higher safety margin than standard riser or general-purpose cable.
• Stranded 100% Copper Conductors: Stranded bare copper conductors give consistent conductivity and flexibility for easier routing and reliable signal transfer.
• Aluminum Foil Shielding: The foil shield reduces electromagnetic interference so audio, alarm and communication signals remain clear.
• 300V, CL3 Power-Limited Rating: A 300V rating and CL3 designation make it appropriate for thermostats, security systems and other low-voltage power-limited circuits.
• UV Resistant Jacket: UV resistance is useful for exposed runs in certain indoor/outdoor transition zones where sunlight exposure may occur.
• Multiple Applications: Intended for fire alarm, burglar alarm, public address, intercoms, telephone stations and access control installations.

Who It's For

This cable is best for electrical contractors, security system installers, and facility maintenance teams who must run low-voltage control wiring through plenum spaces or alongside other services and need a shielded, flexible conductor. The plenum rating and shielding make it especially appropriate for commercial buildings, data closets and areas where air handling pathways are used.

It may be less appropriate for heavy power distribution or high-voltage uses beyond CL3 power-limited circuits, or for projects that require armored or direct-burial cable. Those needing thicker conductors for high-current loads should look at power-specific cable types instead.

Pros & Cons

Pros

• Good conductivity and flexibility from stranded pure copper conductors, making installation easier in tight runs.
• Effective aluminum foil shielding that customers report helps maintain clear signals and reduces interference.
• Plenum-rated CMP jacket provides higher flame retardancy for ceiling and air-handling spaces.
• 300V CL3 rating covers common low-voltage control and alarm applications while remaining power-limited.

Cons

• Some customers describe the cable as relatively thin, which may feel less robust for certain handling conditions.
• The shielded foil construction can be slightly more difficult to terminate than unshielded cable for inexperienced installers.

Specifications

Conductor	Stranded bare copper
Count	18/4 (18 AWG, 4 conductors)
Shielding	Aluminum foil shield
Rating	CMP / CL3P, 300V
Applications	Fire alarm, security, intercom, PA, telephone, access control
Jacket	Plenum-rated, UV resistant

Our Verdict

The SYSTON 18/4 plenum-rated shielded control cable is a practical, cost-effective option for low-voltage control and communication wiring in commercial and institutional settings. Its stranded copper conductors, aluminum foil shielding and CMP jacket offer a reliable combination of conductivity, interference protection and fire safety for plenum runs, making it good value for installers who need a flexible, code-compliant cable for alarm and communication systems.

Frequently Asked Questions

Is this cable suitable for plenum air spaces?
Yes, it is CMP plenum-rated and designed for use in plenum spaces such as ceiling air-handling pathways.

Can it be used for outdoor runs?
The jacket is UV resistant for some exposed conditions, but it is primarily intended for indoor and plenum-rated installations; use outdoor-specific rated cable for direct burial or prolonged outdoor exposure.

Will the foil shield reduce interference for audio and alarm signals?
Yes, the aluminum foil shield helps block electromagnetic interference and customers report improved signal clarity in sensitive applications.