Different wiring systems sharing same racewy

[JdoubleU]

Can you mix 120 volt circuit with 4-20 Milliamp signal wiring? I need to run a race way up to water level reading that has 120 volt magnets that give level reading and a 4-20 Milliamp input. I would like to just use one raceway. The 4-20 cable in shielded. From what I was told you don't have noise issues with 4-20 ma signal wiring.

 

[Dennis Alwon]

Can you mix 120 volt circuit with 4-20 Milliamp signal wiring? I need to run a race way up to water level reading that has 120 volt magnets that give level reading and a 4-20 Milliamp input. I would like to just use one raceway. The 4-20 cable in shielded. From what I was told you don't have noise issues with 4-20 ma signal wiring.

Look at 300.3(C)

 

[don_resqcapt19]

Look at 300.3(C)

And the FPN that follows that section.

 

[JdoubleU]

Look at 300.3(C)

Would the 4-20 ma signal be concidered a class 2 or 3 circuit. If so I don't think I can do this.

 

[Dennis Alwon]

Would the 4-20 ma signal be concidered a class 2 or 3 circuit. If so I don't think I can do this.

I am not the one to ask. Perhaps I should know but I don't. Never studied the class differences.

 

[Pierre C Belarge]

The way to determine if they are Class 2 or Class 3 is to see what source supplies the conductors. Class 2 or Class 3 are listed and labeled as such. Maybe the designer of the system knows.

Don't forget about the insulation values required if the system supply is not Class 2 or 3.

 

[Dennis Alwon]

So, Pierre, do you know what determines if it is class 2 or class 3. Is there something in the design of the tranys or something like that?

 

[raider1]

So, Pierre, do you know what determines if it is class 2 or class 3. Is there something in the design of the tranys or something like that?

Dennis,

Take a look at Chapter 9 Table 11(A) and 11(B) to see the difference in power limitations for Class 2 and Class 3 power supplys.

Chris

 

[raider1]

Can you mix 120 volt circuit with 4-20 Milliamp signal wiring? I need to run a race way up to water level reading that has 120 volt magnets that give level reading and a 4-20 Milliamp input. I would like to just use one raceway. The 4-20 cable in shielded. From what I was told you don't have noise issues with 4-20 ma signal wiring.

My guess would be that the 4-20 Milliamp input would be either a Class 2 or 3 circuit and not permitted to be installed in the same raceway with a 120 volt circuit.

You may want to look at 725.130(A) Exception #2.

Chris

 

[Pierre C Belarge]

So, Pierre, do you know what determines if it is class 2 or class 3. Is there something in the design of the tranys or something like that?

Dennis

'08 - take a look at 725.121(A)(1)-(A)(5).