18/6 250ft Thermostat Wire Cable - Solid Copper, CL2 Low Voltage

In this review of the 18/6 250ft thermostat cable from NATIONAL Wire&Cable, the bottom line is straightforward: it is a good choice for installers and homeowners who need reliable low voltage connections and prefer products made in the USA. The review focuses on real-world use with HVAC and thermostat systems, highlighting the main reason to buy: solid copper conductors that deliver strong conductivity and predictable signal transmission for thermostats and doorbells. It is not a premium armored cable, but it performs well where flexibility and clear signal paths matter.

Key Features

• Made in USA: Manufactured in New York since 1972, the cable gives buyers confidence in consistent production and quality control.
• 100% Solid Copper Conductors: Solid copper cores improve electrical conductivity and reduce resistance for accurate thermostat signals.
• CL2 ETL Listed: Rated for low voltage applications, the cable meets safety expectations for in-wall thermostat and doorbell runs.
• Durable construction: Built to withstand typical installation stresses so connections remain secure over time.
• Multi-conductor design: Six conductors simplify hookups for multi-stage HVAC systems and additional control circuits.
• Lifetime warranty: Backed by the manufacturers lifetime satisfaction promise, providing support for long-term use.

Who It's For

The cable is best for HVAC contractors, electricians, and DIY homeowners who need a straightforward, CL2-rated low voltage wire for thermostats, doorbells, or simple control wiring. Those who value solid copper conductors and prefer a product made domestically will appreciate the consistency and conductivity this cable offers.

It is less appropriate for runs that demand heavy mechanical protection, such as exposed outdoor runs or areas requiring armored cable. Customers needing extra abrasion resistance or specialized high-flex conductors for constant motion should consider purpose-built alternatives.

Pros & Cons

Pros

• Solid copper conductors deliver reliable electrical performance for thermostats and low voltage devices.
• CL2 ETL listing means it is suitable for in-wall low voltage installations in residential and commercial settings.
• Produced in the USA with a long manufacturing history, offering traceable quality and a lifetime warranty.
• Six conductors allow straightforward wiring for multi-stage HVAC systems and extra control lines.

Cons

• Some users report the jacket and conductors feel somewhat fragile during handling, so careful routing and strain relief are advised.

Specifications

Conductor type	100% solid copper
Gauge	18 AWG
Conductors	6 (18/6)
Length	250 ft
Rating	CL2 ETL listed for low voltage
Country of manufacture	Made in USA (New York)
Warranty	Lifetime satisfaction warranty

Our Verdict

The 18/6 250ft thermostat cable is a practical, value-oriented choice for most thermostat and HVAC control wiring projects because of its solid copper conductors, CL2 rating, and domestic manufacture. Installers and homeowners who need reliable signal transmission and an in-wall approved low voltage cable will find good performance for the price, while those requiring heavier-duty or more flexible jacketed wire should consider specialized alternatives.

Frequently Asked Questions

Is this cable safe for in-wall thermostat installation?
Yes. It is CL2 ETL listed, which indicates it meets common safety standards for in-wall low voltage thermostat and doorbell wiring.

Can this cable be used with smart thermostats?
Yes. The solid copper conductors provide consistent signal and power paths compatible with most smart thermostat installations.

Does the cable come with a warranty?
Yes. The manufacturer backs the cable with a lifetime satisfaction warranty.