what is the difference

[copper chopper]

can someone tell me in la-mans terms or maybe give examples of a class 1 or class 2 circuit...
what if its 10 volts dc and I run it in THHN along with 120 volt ac wires, I dont see the issue here.

 

[infinity]

A class 2 circuit fed from a class 2 power supply cannot be in the same raceway as power or lighting conductors.

 

[texie]

can someone tell me in la-mans terms or maybe give examples of a class 1 or class 2 circuit...
what if its 10 volts dc and I run it in THHN along with 120 volt ac wires, I dont see the issue here.

As infinity said. Just keep in mind that just because it is only 10 volt DC that in of itself does not mean that it is class 2. Class 2 carries with it very specific power limiting properties.

 

[copper chopper]

they need to do better job in the code book on this issue, however if 10 volt dc is sourced from a dimmer on the same 120 volt circuit as is in the raceway, what class does that fall under.I still think its class 1.

 

[GoldDigger]

they need to do better job in the code book on this issue, however if 10 volt dc is sourced from a dimmer on the same 120 volt circuit as is in the raceway, what class does that fall under.I still think its class 1.

That dimmer may be a Class 2 power supply with respect to the 0-10V DC output. But if you want to run that voltage in the same raceway as RELATED power wiring, you cannot do it unless you re-categorize the exact same output circuit as Class 1 and run it using Class 1 wiring methods. That option to re-cagtegorize the same circuit to take advantage of a different set of rules is often very useful. Note carefully that you cannot freely mix and match Class 1 and Class 2 identification for the same circuit. You have to pick one or the other and follow that set of rules only.
Looking at it another way, the fact that the source of power in a circuit is Class 2 does not mean that you can only wire it using Class 2 rules.
But once you re-categorize it as Class 1, you cannot connect it to a device which requires that its power be supplied from a Class 2 source!

 

[infinity]

they need to do better job in the code book on this issue, however if 10 volt dc is sourced from a dimmer on the same 120 volt circuit as is in the raceway, what class does that fall under.I still think its class 1.

If you're using something like a Lutron Eco ballasted system you're permitted to use the control as Class 1 and run the control and power conductors together.

Here's some good info from Lutron regarding Class 1 and Class 2 control:

http://www.lutron.com/technicaldocumentlibrary/366-606_fds_tg.pdf

 

[kwired]

they need to do better job in the code book on this issue, however if 10 volt dc is sourced from a dimmer on the same 120 volt circuit as is in the raceway, what class does that fall under.I still think its class 1.

The output side may be class 2.

Class 2 circuits are power limited and therefore have less restrictions than non power limited circuits. The voltage and current levels are low enough they are considered little risk for electric shock and little risk from overheating as there is not enough available power for those risks to be very high.

Take a large battery and even though the voltage may be low enough that there is little risk of shock, there is still enough power available to cause some significant heating.

We need to run class 1 and 2 in separate wiring methods to reduce risks of cross over faults energizing the class 2 circuit with class the class 1 power supply.