18/3 Low Voltage Security Sound Alarm Cable 900 ft - Plenum Rated CMP

Our review of the 18/3 Low Voltage Security Sound Alarm Cable finds it best suited for installers and facility managers who need a reliable, plenum-rated control cable for fire alarm, security, and intercom systems; the single biggest reason to buy is its combination of CMP plenum rating and full aluminum foil shielding, which together keep signals clear while meeting the stricter fire safety requirements for ceiling plenums and air handling spaces.

Key Features

• Multiple applications: Works for fire alarm, security burglar alarm, public address, intercoms, telephone stations and other low-voltage power-limited circuits, giving installers a versatile cable for many site needs.
• Pure copper conductors: Stranded bare copper conductors provide consistent conductivity and flexibility for routing through walls and conduit without excessive stiffness.
• Aluminum foil shielding: The foil shield limits electromagnetic interference so sensitive signals remain clear for communications and instrumentation.
• CMP plenum-rated: The plenum rating means the jacket meets higher flame and smoke standards, making it appropriate for ceiling plenums and air distribution spaces.
• 300V CL3 rating: The 300V insulation and CL3 classification ensure it is suitable for Class 3 power-limited low-voltage installations such as access control and thermostats.

Who It's For

This cable is aimed at professional electricians, AV integrators, and building maintenance teams who need a single, compliant cable for alarm, voice and low-voltage control runs in commercial or multi-family buildings. Its plenum rating and shielding make it a practical choice where code requires plenum-rated materials and where electromagnetic interference could be a concern.

Home users with simple runs that do not require plenum-rated cable may find less expensive non-plenum alternatives adequate; likewise, projects requiring very heavy-gauge conductors or mains voltage distribution should look for a cable designed for those specific electrical loads.

Pros & Cons

Pros

• Good build quality with stranded bare copper conductors that balance conductivity and flexibility.
• Effective aluminum foil shielding that customers report keeps signals clean and minimizes noise.
• Plenum-rated CMP jacket offers higher flame resistance for use in air-handling spaces.
• Works across many low-voltage applications, making it a versatile stock cable for installers.

Cons

• Some customers describe the cable as relatively thin in overall thickness, which may concern users expecting heavier insulation.

Specifications

Conductor	Stranded bare copper, 18 AWG, 3 conductors
Length	900 ft
Shielding	Aluminum foil shield
Ratings	CMP plenum rated, CL3P, FPLP, FT6
Voltage	300V (low-voltage CL3)
Applications	Fire alarm, security, PA, intercoms, telephone, access control

Our Verdict

The 18/3 Low Voltage Security Sound Alarm Cable is a solid choice for commercial installs that require plenum-rated cable and reliable shielding; it delivers good conductivity and versatility across alarm and communication systems while offering value for installers who stock a single multiuse cable.

Frequently Asked Questions

Is this cable safe for plenum spaces?
Yes. It is CMP plenum rated and designed for use in ceiling plenums and air handling spaces where higher flame and smoke standards apply.

Will the shielding stop interference in audio and alarm lines?
The aluminum foil shield helps prevent EMI from disrupting signals and customers report improved clarity in communications and LED lighting control runs.

Can this cable power devices directly?
It is a 300V CL3 rated, power-limited low-voltage cable suitable for Class 3 devices like access control and thermostats, but not intended for mains voltage power distribution.