18/3 Low Voltage Security Sound Alarm Cable 100 ft - Plenum Rated

Our review examines the 18/3 Low Voltage Security Sound Alarm Cable in a 100 ft spool and finds it best suited for installers and DIYers who need a reliable, plenum-rated cable for low-voltage control systems. The single biggest reason to buy is the combination of stranded bare copper conductors and an aluminum foil shield, which together deliver dependable conductivity and protection from EMI for systems like fire alarms, access control, and public address wiring. In this review the cable stands out for safety compliance and consistent signal integrity in power-limited applications.

Key Features

• Multiple Applications: Compatible with fire alarm, security burglar alarm, public address, intercoms and other low-voltage power-limited circuits, making it versatile on job sites.
• Pure Copper Conductors: Stranded bare copper conductors provide flexibility and good conductivity for reliable connections and long runs.
• Aluminum Foil Shielding: The foil shield helps block electromagnetic interference so sensitive communication and instrumentation signals remain clear.
• CMP Plenum Rating: Plenum-rated CMP/CL3P/FT6 construction allows safe installation in air handling spaces such as ceilings and plenum areas.
• 300V CL3 Rating: Rated to 300V and compliant with Class 3 power-limited standards, suitable for thermostat, security and audio/visual low-voltage use.

Who It's For

This cable is a practical choice for electricians, low-voltage contractors and facilities maintenance teams who need a plenum-rated cable that supports a variety of systems including nurse call, access control, telephone stations and PA systems. The stranded copper and shielding make it particularly useful where runs pass near other electrical equipment or through shared spaces that can introduce EMI.

Home hobbyists and light DIYers can use this product for cabinet lighting or simple security installs, but those who do not require plenum-rated cable or need heavier gauge power conductors should consider alternatives designed for higher current or non-plenum spaces.

Pros & Cons

Pros

• Good wiring versatility for many low-voltage systems, reducing the need for multiple cable types.
• Shielding effectively minimizes EMI, which customers noted improves signal stability in sensitive runs.
• Stranded copper construction is flexible and easy to route through conduits and around corners.
• Plenum-rated CMP and 300V CL3 rating provide an extra safety margin for air-handling spaces.

Cons

• Some users report the jacket and conductor bundle feels thin compared with heavier power cable, so it may not suit high-stress mechanical environments.

Specifications

Conductor	18 AWG stranded bare copper
Conductors	3
Shielding	Aluminum foil shield
Length	100 ft
Voltage Rating	300V (CL3)
Fire Rating	CMP / CL3P / FT6 (Plenum rated)

Our Verdict

The 18/3 Low Voltage Security Sound Alarm Cable is a solid, cost-effective option for professionals and serious DIY installers who need a plenum-rated, shielded cable for low-voltage systems. Its stranded copper conductors and foil shielding deliver reliable signal integrity, and the CMP rating makes it appropriate for ceiling and air-handling spaces, offering strong value for typical security, alarm and communication installs.

Frequently Asked Questions

Is this cable safe for plenum installation?
Yes, it carries a CMP/CL3P/FT6 plenum rating suitable for use in air-handling spaces and ceilings.

Will the shielding help with interference?
The aluminum foil shield reduces electromagnetic interference and helps maintain clear signal transmission for sensitive low-voltage circuits.

Can this cable handle power-limited devices like thermostats and security panels?
Yes, it is rated 300V and CL3 for power-limited applications such as thermostats, security systems and audio/visual equipment.