What is the NEC classification for thermostat wire?

The National Electrical Code (NEC) classifies thermostat wire as Class 2. This classification applies to circuits that have a low voltage, generally under 60 volts, and provides an additional layer of safety by allowing for the use of specific installation methods and materials. Class 2 circuits are recognized for their limited energy and inherent low risk of electric shock or fire, making them suitable for use in control circuits, such as those found in thermostat applications.

Class 2 wiring is designed to be less hazardous and is subject to less stringent installation requirements compared to higher classifications. This makes it particularly suitable for low-voltage applications, as seen with thermostat wiring, which typically operates in the range of 24V to 30V.

Understanding these classifications is important for technicians to ensure compliance with safety standards and to properly install and troubleshoot electrical and HVAC systems.