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Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable
National HVAC Parts

Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable

SKU: NHVAC-THER-TKK9EW Brand: National HVAC Parts
$59.00 $79.65

Order before 3PM CST — ships same day.
Standard delivery 2-5 business days. Express options at checkout.

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Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable

Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable — solid copper thermostat cable for connecting your thermostat to the furnace or air handler. 5-conductor wire handles standard heating and cooling systems.

Key Features

  • Solid copper conductors for reliable signal transmission
  • CL2-rated for in-wall installation per NEC code
  • 5 conductors — covers heat, cool, fan, common, and reversing valve
  • 250-foot spool — enough for most residential runs

Specifications

  • Gauge: 18 AWG
  • Conductors: 5
  • Length: 250 feet
  • Rating: CL2 (in-wall rated)
  • Material: Solid copper

What's Included

  • Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable

Ships same-day from our Houston warehouse on orders placed before 3PM CST.

Frequently Asked Questions

How many conductors do I need?

2-wire for heat only. 4-wire for basic heat/cool. 5-wire for heat/cool with common wire (needed for smart thermostats). 8-wire for heat pumps with auxiliary heat. When in doubt, run more conductors than you think you need.

Can I use this wire for a smart thermostat like Nest or Ecobee?

Yes, but smart thermostats require a "C" (common) wire, so you need at least 5 conductors (18/5). If you currently have 18/4, you may need to upgrade the wire.

Is this rated for in-wall installation?

Yes, CL2-rated wire is approved for permanent in-wall installation per the National Electrical Code.

What is the maximum run length?

18 AWG thermostat wire can run up to about 250 feet without voltage drop issues. For runs over 200 feet, consider using 16 AWG wire.

Shipping Information

  • Orders placed before 3PM CST ship same business day
  • Standard delivery: 2-5 business days
  • Express shipping available at checkout
  • Free shipping on orders over $75
  • Tracking number emailed upon shipment

Return Policy

  • 30-day returns on unused parts in original packaging
  • Electrical parts (capacitors, contactors, control boards) are final sale once installed
  • Email support@nationalhvacparts.com to initiate a return
  • Refunds processed within 5-7 business days

Frequently Asked Questions

Does this Thermostat Wire & Electrical fit my National HVAC Parts Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable?
Yes. This is the factory-specified OEM thermostat wire & electrical for the National HVAC Parts Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.
How do I replace the thermostat wire & electrical on my National HVAC Parts Thermostat Wire 18/5 250 Feet CL2 Solid Copper HVAC Cable?
Refer to your equipment service manual for model-specific steps. General approach: turn off power, photograph connections, remove old part, install new part, restore power and test. For gas components, hire a licensed technician. Email info@nationalhvacparts.com for guidance.
What symptoms mean I need a new thermostat wire & electrical?
Common symptoms: unusual noises, intermittent operation, complete failure, or visible damage. Visit our diagnostic hub for symptom-based troubleshooting.
Is this thermostat wire & electrical compatible with Bryant or Payne too?
Many National HVAC Parts parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.
Should I use OEM or aftermarket for my National HVAC Parts thermostat wire & electrical?
OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.
How fast does National HVAC Parts ship?
Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.
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