# ac and dc circuits in the same cable tray or race way



## BBQ (Nov 16, 2010)

Sure, in most cases.


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## stedan (Jun 23, 2010)

how about if it is a control circuit? 24 volt dc with 120 v ac circuits


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## All-Circuits (May 31, 2011)

yes you can, and they are not considered current carrying conductors either, so you don't even have to worry about derating.


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## BBQ (Nov 16, 2010)

stedan said:


> how about if it is a control circuit? 24 volt dc with 120 v ac circuits


Depends on the class of control circuits, Class 2 or 3 no, Class 1 I think yes but not sure.


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## Loose Neutral (Jun 3, 2009)

Do the cables have to have the same voltage ratings?


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## All-Circuits (May 31, 2011)

no, as long as they have the same insulation type. For example contol wire gauge 16 can be pulled with #6 awg thhn as long as the control wires are also thhn.


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## raider1 (Jan 22, 2007)

stedan said:


> how about if it is a control circuit? 24 volt dc with 120 v ac circuits





BBQ said:


> Depends on the class of control circuits, Class 2 or 3 no, Class 1 I think yes but not sure.


If the control circuit is a class 2 or 3 circuit the you can't install them in the same raceway with other power and lighting conductors (See 725.139)

If the control circuit is a Class 1 circuit then you can install it in the same raceway with power conductors provided that they are functionally associated with the power supply circuit. (See 725.48(B)(1))

Chris


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## raider1 (Jan 22, 2007)

Loose Neutral said:


> Do the cables have to have the same voltage ratings?





All-Circuits said:


> no, as long as they have the same insulation type. For example contol wire gauge 16 can be pulled with #6 awg thhn as long as the control wires are also thhn.


The conductors must have a voltage rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway. (See 300.3(C)(1))

Chris


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## Loose Neutral (Jun 3, 2009)

raider1 said:


> The conductors must have a voltage rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway. (See 300.3(C)(1))
> 
> Chris


That's what i thought, so he may have to use a divider on the 24v.


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## All-Circuits (May 31, 2011)

Please read nec Sec. 300.3(c)(1). it reads as follows. Conductors of ac and dc circuits, rated 600 volts, nominal, or less, shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum curcuit voltage applied to any conductor within the enclosure, cable, or raceway. This allows ac and dc circuits together in the same raceway, and the insulation rating of the highest rated voltage needs to be the same insulation rating for all other conductors in that raceway. please read the section again if you need to, but don't apply a divider....That's just ignorant of the code.


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## Loose Neutral (Jun 3, 2009)

Maybe his 120v CT jacket is rated 600v and his 24v jacket is rated 300v. Thats why I said he may. Just saying. We don't have all the facts and the question may have been intended just as a general question.


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## raider1 (Jan 22, 2007)

Loose Neutral said:


> Maybe his 120v CT jacket is rated 600v and his 24v jacket is rated 300v. Thats why I said he may. Just saying. We don't have all the facts and the question may have been intended just as a general question.


If the 24v control system has a 300 volt rated cable it is most likely a Class 2 or 3 circuit and can not be installed in the same raceway with power conductors.

Chris


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## Big John (May 23, 2010)

All-Circuits said:


> ...Please read the section again if you need to, but don't apply a divider....That's just ignorant of the code.


 Not so fast, if the 24 volt circuit he asked about is a classified power-limited circuit then the divider may well be required.

Like _Raider1 _said, check article 725.

-John


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## All-Circuits (May 31, 2011)

raider1 said:


> If the 24v control system has a 300 volt rated cable it is most likely a Class 2 or 3 circuit and can not be installed in the same raceway with power conductors.
> 
> Chris


 Agreed, if that is the senerio, then the 600v rated conductor for 24volt control wire would be better solution then divider, besides, I think a divider in leu using the right insulated wire would be a poor installation. But you never know with some people.


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## All-Circuits (May 31, 2011)

Big John said:


> Not so fast, if the 24 volt circuit he asked about is a classified power-limited circuit then the divider may well be required.
> 
> Like _Raider1 _said, check article 725.
> 
> -John


 I think we need clarification from the poster boy.


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## stedan (Jun 23, 2010)

Thanks for all replies,i was pointed in the right direction with them the install is a class 2 so i will seperate. Thanks


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## BBQ (Nov 16, 2010)

All-Circuits said:


> Agreed, if that is the senerio, then the 600v rated conductor for 24volt control wire would be better solution then divider, besides, I think a divider in leu using the right insulated wire would be a poor installation. But you never know with some people.


Again, if it is a class 2 or class 3 circuit, it does not matter what insulation is used, it cannot be in the same raceway as the power and lighting conductors.

If it is Class 1 and the right insulation is used then it can be in the same raceway.


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## don_resqcapt19 (Jul 18, 2010)

BBQ said:


> ...
> If it is Class 1 and the right insulation is used then it can be in the same raceway.


 Only if the Class 1 circuit is functionally associated with the power circuits. 725.48(B)(1).


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