Does anyone know what Articles of the NEC apply to the wiring that goes from a thermostat to an air conditioner unit? It seems like Articles 422, 430, and 440 all deal with wiring from the utility service to the air conditioner unit but not from the air conditioner unit to the thermostat. I was thinking that maybe Article 725 in section III might be what I need to look at but am not sure because I'm a little confused about what constitutes a class 2 or 3 circuit. Can someone knowledgeable in this area help me determine what parts of the NEC I have to look at?
NEC Code Relating To Thermostat Wiring
- Thread starter DSoto
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- Bremerton, Washington
Its almost always an Article 725 Class II Circuit. Look at the power supply or transformer and it will be labeled as to the circuit type. For a Class II circuit you can not be in the same enclosure racway or box as the power conductors, even if the thermostat cable is 600 volts. See 725.55
bphgravity
Senior Member
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- Florida
If run exposed on the outside of the building or structure, make sure the cable is listed sunlight resistant and listed for use in a wet location.
See this from UL: http://database.ul.com/cgi-bin/XYV/...=versionless&parent_id=1073992408&sequence=1
See this from UL: http://database.ul.com/cgi-bin/XYV/...=versionless&parent_id=1073992408&sequence=1
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