[mmajoris]

Ok, so I know that code 400.8 covers flex wire in walls, so a big nono to zip wire. And naturally, you would have to be a crazy person to hide a wall wart. My question is if there are codes preventing the use of low voltage wire in walls, how does standard thermostat wire carrying 24vac get around this code?

If it's somehow exempt, could I then use a 24vac wall plug and wire it to thermostat wire, bury it in a wall, and run it to my thermostat?

I've put together the circuit for a relay and transformer to allow me to use a smart thermostat to control my fireplace. No questions on that, just need to see what I can do to keep it up to code.

 

[betelgeuse]

Ok, so I know that code 400.8 covers flex wire in walls, so a big nono to zip wire. And naturally, you would have to be a crazy person to hide a wall wart. My question is if there are codes preventing the use of low voltage wire in walls, how does standard thermostat wire carrying 24vac get around this code?

Zip cord (SPT cable) doesn't meet the UL certification requirements for flammability, smoke contribution, etc and bell (thermostat) does.

 

[RAL238]

Cable that is run in walls has to have a fire resistance rating. Thermostat wire is CL2 or better. Zip cord doesn't have a rating that allows it to be run in walls.



https://www.cablewholesale.com/support/technical_articles/confusing_cable_terms.php

 

[mmajoris]

Ok great. So I should have no problems plugging in a wall plug in an accessible location in the basement, wiring thermostat wire directly to it, and chasing that wire through the walls to the thermostat correct?

 

[RAL238]

Ok great. So I should have no problems plugging in a wall plug in an accessible location in the basement, wiring thermostat wire directly to it, and chasing that wire through the walls to the thermostat correct?

Yes, that would be ok.

 

[RAL238]

Here is a chart that shows what cable ratings can be substituted for lower rated cables.

 

[surferdude2]

Is the transformer marked and listed for class 2 application? It must say that to be code compliant.

 

[mmajoris]

It is indeed. Class II Transformer - 24 Volt AC, 40 VA, UL/CSA Approved

 

[surferdude2]

Class II is not the same as class 2.

 

[mmajoris]

Well, that's good to know. I was completely unaware of that piece of information. Thanks for the heads up.