control/monitoring wiring

[splinetto]

What code section would this type of wiring fall under?......Some are 24v and some 120v ....Im helping out on the install and am trying to learn as much as I can..... #2 How do you calc pipe fill for this type of install? Thank you

 

[raider1]

Take a look at Article 725, Class 1, Class 2, and Class 3 remote-control, signaling, and power limited circuits.

Chris