NEC 725.136 - Class 2 circuit question

[KarlS]

I installed a Bard HVAC unit on a metal building. The power wiring and Tstat wiring are installed in the same conduit. The conduit is less than 6" long. The UL inspector stated I cannot run Class 2 circuits in the same conduit as power wiring. The NEC 725 section is not much help as it does not specifically mention T-stat wiring. The wire is 600V rated #18 and the same conductor type as the power wiring. Is he correct? Should it be seperated?

 

[WorkSafe]

Well, I do believe the TSTAT instructions will state not to place the tstat wires near high voltage wire because of interference. Now, whether or not that 6" will effect it.......

 

[raider1]

Take a look at 725.130(A) Exception #2.

Chris

 

[qcroanoke]

Take a look at 725.130(A) Exception #2.

Chris

Bingo!.........

If the control xfmr is marked class 2 just get a sharpie and black it out and voila! It's class1 if you comply by wiring it in a class 1 method.

 

[KarlS]

Thanks for getting back with me. I went out and checked the 24V transformer and it is marked class 2. I see in the NEC this is permitted but I don't think this UL inspector will allow me to do it. I guess otherwise its a class 2 circuit?

 

[raider1]

Thanks for getting back with me. I went out and checked the 24V transformer and it is marked class 2. I see in the NEC this is permitted but I don't think this UL inspector will allow me to do it. I guess otherwise its a class 2 circuit?

Is this being field evaluated by UL?

Your choices are run this as a class 2 circuit and keep it separate from the power wiring or re-classify it as a class 1 circuit and wiring it accordingly.

Chris

 

[KarlS]

The building is being field evaluated by UL.

I asked the inspector if he would allow me to re-classify it as a class 1 circuit. He would not allow it and stated by removing the class 2 marking on the transformer you remove the UL rating on the HVAC unit. I guess I run another conduit.

Thanks for everyones help!

 

[raider1]

The building is being field evaluated by UL.

I asked the inspector if he would allow me to re-classify it as a class 1 circuit. He would not allow it and stated by removing the class 2 marking on the transformer you remove the UL rating on the HVAC unit. I guess I run another conduit.

Thanks for everyones help!

Did you ask the UL inspector about 725.130(A) Exception #2?

Chris