460VAC Motor T-Stat for Class I, Division 2

[katan840df]

Looking for clarification if a 460VAC motor t-stat, wired to a 24VDC input on a plc is acceptable to run in the same flexible conduit as the 460VAC power wires. Motor Leads are #12 AWG THHN, and T-Stat wires are #16 AWG THHN. Area Classification is Class I, Division 2, Groups C&D.

 

[Dsg319]

I would almost say the 24VDC wiring is a class 2 circuit. I’m not sure of any exception that allows them the be installed with power conductors.

Will be curious to see what others have to say. Than again does that motor terminal box only have one entry?

 

[katan840df]

Yes, the motor terminal box only has one entry.

 

[petersonra]

I would almost say the 24VDC wiring is a class 2 circuit. I’m not sure of any exception that allows them the be installed with power conductors.

Will be curious to see what others have to say. Than again does that motor terminal box only have one entry?

What makes you think it's a class 2 circuit? Just because it's 24 volt DC does not make it a class 2 circuit.

 

[Dsg319]

What makes you think it's a class 2 circuit? Just because it's 24 volt DC does not make it a class 2 circuit.

Just assumed it was. What class power supplies do you come across typically for PLC inputs?

 

[petersonra]

Just assumed it was. What class power supplies do you come across typically for PLC inputs?

Most times digital inputs end up being class 1 circuits. A class 2 circuit requires a class 2 power supply most times and they are limited to 100 watts. So unless there is some special reason we need a class 2 circuit, we would not use a class 2 power supply.

 

[Dsg319]

Most times digital inputs end up being class 1 circuits. A class 2 circuit requires a class 2 power supply most times and they are limited to 100 watts. So unless there is some special reason we need a class 2 circuit, we would not use a class 2 power supply.

So basically he just needs to confirm the power source. And if it is a class 1 he should be good?

 

[katan840df]

Yes, I am not using a Class 2 power supply. Thanks for the answers.

 

[petersonra]

So basically he just needs to confirm the power source. And if it is a class 1 he should be good?

I don't think there is such a thing as a class 1 power supply. It is either a class 2 power supply or it isn't. It is a class 1 circuit if it is a control circuit and meets the power limits set for class 1 circuits in article 725, generally this is just a fuse or cb to limit the max current.