Southwire 18-5CS Thermostat Wire 18 Awg 5 Conductor

Product Description

The SOUTHWIRE 18-5CS is an 18 AWG, 5-conductor thermostat wire supplied in a 250-foot coil. Designed for low-voltage control wiring in heating and cooling systems, it connects thermostats to HVAC equipment such as furnaces, air handlers, heat pumps, and condensing units. Licensed HVAC technicians and contractors use this wire during new installations and system retrofits where multiple control functions require separate conductors. The 18 AWG gauge and 5-conductor configuration make it suitable for standard residential and light commercial thermostat circuits.

This wire is commonly used in residential and light commercial HVAC applications where low-voltage thermostat wiring is required. Typical installations include running wire from a thermostat to a furnace, air handler, or heat pump control board. The 5-conductor design accommodates systems that require heating, cooling, fan, common, and reversing valve or auxiliary heat terminals. The 250-foot coil length suits most single-system residential jobs with wire to spare for longer runs.

Key Features

• 18 AWG conductor gauge suited for low-voltage thermostat control circuits
• 5 conductors provide wiring capacity for multi-function HVAC systems including heat pumps
• 250-foot coil length covers most residential and light commercial installation runs
• Low-voltage rated construction designed for thermostat and control wiring applications

Compatibility

Designed as a standard low-voltage thermostat wire replacement or new-installation supply for residential and light commercial HVAC systems using 18 AWG 5-conductor control wiring.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified electrician in accordance with applicable local codes and NEC guidelines for low-voltage wiring. Power down the HVAC system at the disconnect and thermostat before making any wiring connections. Avoid routing thermostat wire in close parallel runs with line-voltage conductors, as this can introduce interference. Secure wire runs with appropriate staples or clips rated for low-voltage cable to prevent damage.

Technical Specifications

• Conductor Gauge: 18 AWG
• Number of Conductors: 5
• Wire Length: 250 feet

Standard Information

• Brand: SOUTHWIRE
• Manufacturer Part Number: 18-5CS