Class 1,2 &3

[allbrite]

I am an electrician in S. Florida and I am trying to find out what class the wiring from a air handling control transformer/thermostat to a condensing unit would be.

I am trying to prove that the NEC allows the control and power wiring to a condensing unit can share the same raceway. Thanks

 

[bphgravity]

Re: Class 1,2 &3

The class of the circuit will be determined by the class of the power source. Most likely, the transformer for the HVAC system is class 2. Class 2 and Class 3 circuits are not permitted in the same raceway as power conductors. See section 725.55(A)

 

[allbrite]

Re: Class 1,2 &3

According to article 725.52 (A) Exception 2, class 2 & 3 circuits can be reclassifed and installed as class 1 as long as the markings stating the class of the transromer is removed. So I believe that would allow me to run the low voltage wiring with the feed.

 

[bphgravity]

Re: Class 1,2 &3

Yes, that is correct.

Also, the reclassified conductors must have a 600V rating and overcurrent protection in accordance with 725.23

 

[peter d]

Re: Class 1,2 &3

Originally posted by allbrite:
According to article 725.52 (A) Exception 2, class 2 & 3 circuits can be reclassifed and installed as class 1 as long as the markings stating the class of the transromer is removed. So I believe that would allow me to run the low voltage wiring with the feed.

Be careful. Now the entire low voltage circuit has to be a class 1 wiring method. You can't use thermostat cable beyond the raceway in which the line and low voltage circuits run. You would have to use NM, MC, etc for all the low voltage and all the way to the thermostat and other controls. The thermostat would also have to be mounted on a box.

Unless you can justify the potential added labor and cost for reclassifying, it doesn't make sense.