# Line voltage and low voltage



## HARRY304E (Sep 15, 2010)

sparkplug said:


> Can I put line voltage and low voltage wires in the same conduit as long as the insulation is rated for 600 volts?


Yes look at ARTICLE 300 NEC 2008:thumbup:


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## danickstr (Mar 21, 2010)

also it is OK to reclass class 2 rated wiring as class 1 if you follow all the rules of class 1 (such as using 600v wire), which gives you more leeway to run them together with Line voltage. 720 is the article or 725


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## mikeh32 (Feb 16, 2009)

I was told that you can not run data/phone in the same. this was just on tuesday in class too


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## Edrick (Jun 6, 2010)

Only an idiot would run low voltage phone or data in parallel or in the same conduit for that matter with line voltage. I don't know if it's against the NEC but it is against any data wiring certifications.


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## macmikeman (Jan 23, 2007)

Edrick said:


> Only an idiot would run low voltage phone or data in parallel or in the same conduit for that matter with line voltage. I don't know if it's against the NEC but it is against any data wiring certifications.


Sounds crackly too....


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## Bob Badger (Apr 19, 2009)

sparkplug said:


> Can I put line voltage and low voltage wires in the same conduit as long as the insulation is rated for 600 volts?





HARRY304E said:


> Yes look at ARTICLE 300 NEC 2008:thumbup:


Lets say maybe, or sometimes



> *300.3(C) Conductors of Different Systems.
> (1) 600 Volts, Nominal, or Less. *Conductors of ac and dc
> circuits, rated 600 volts, nominal, or less, shall be permitted
> to occupy the same equipment wiring enclosure, cable, or
> ...


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## sparkplug (Jan 12, 2010)

Thanks a lot guys


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## danickstr (Mar 21, 2010)

Simple control wires are fine there, and chance of interference on something like 24v momentary signal control is negligible. 

Yes, data and phone are a different story, but typically not run on 600 volt wire.


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## Bob Badger (Apr 19, 2009)

danickstr said:


> Simple control wires are fine there, and chance of interference on something like 24v momentary signal control is negligible.



But the fact you would then have to treat the class 2 or 3 as class 1 makes it much less attractive in most cases.

That would mean if you ran the t-stat wire for a boiler in with the power wires in just a few feet of conduit in the basement you would have to run them all the way to the T-stat in a Chapter 3 wiring method and the T-stat would have to be mounted to a wall box.


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## Shockdoc (Mar 4, 2010)

Bob Badger said:


> But the fact you would then have to treat the class 2 or 3 as class 1 makes it much less attractive in most cases.
> 
> That would mean if you ran the t-stat wire for a boiler in with the power wires in just a few feet of conduit in the basement you would have to run them all the way to the T-stat in a Chapter 3 wiring method and the T-stat would have to be mounted to a wall box.


 No. only within the class 1 range then they can be spliced down to a lower class outside. But let me guess 08 has changed that?


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## mikeh32 (Feb 16, 2009)

danickstr said:


> Simple control wires are fine there, and chance of interference on something like 24v momentary signal control is negligible.
> 
> Yes, data and phone are a different story, but typically not run on 600 volt wire.


i think he said run them next to each other... not on the 600 wire


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## Bob Badger (Apr 19, 2009)

Shockdoc said:


> No. only within the class 1 range then they can be spliced down to a lower class outside. But let me guess 08 has changed that?


No, this has been the code for a long time.


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## Shockdoc (Mar 4, 2010)

Bob Badger said:


> No, this has been the code for a long time.


I see the logic behind it being if for some reason energy is charged into low voltage the wiring downstream is rated for it. Guess I've done a great many violations on many boilers i've wired being that I'd drop my thhn out of the box and splice it over to tstat wiring.


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## Toronto Sparky (Apr 12, 2009)

Seen it done in fire alarm systems.. ie. Maglocks , door holders , exhaust hood shutdown
Isn't that why fire alarm wire has to be rated 250v now?


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