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#94711 - 08/10/05 06:33 AM Mixing DC with AC conductors?  
MikeW  Offline
Member
Joined: Jun 2002
Posts: 35
Michigan
Does the NEC allow 24vdc wires to be run in the same conduit with 120vac conductors?

What code section(s)?

thanks


2017 / 2014 NEC & Related Books and Study Guides

#94712 - 08/10/05 07:21 AM Re: Mixing DC with AC conductors?  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Mike,
Look at 300.3(C)(1), but make sure that you read the FPN that follows that section.
Don


Don(resqcapt19)

#94713 - 08/10/05 12:44 PM Re: Mixing DC with AC conductors?  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,113
Estero,Fl,usa
Just remember that when you mix voltages in an enclosure or raceway you lose any latitide you might have had for "low voltage" in art 725. Everything is now treated like line voltage.


Greg Fretwell

#94714 - 08/13/05 08:17 AM Re: Mixing DC with AC conductors?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
300.3 contains a similar requirement for this situation to one we have here -- That all conductors must be insulated for the highest voltage present.,


#94715 - 08/13/05 09:28 PM Re: Mixing DC with AC conductors?  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Paul,
You have to read and apply the FNP that follows the section that you have cited. The section doesn't really mean what it says.
Don


Don(resqcapt19)

#94716 - 08/14/05 08:12 AM Re: Mixing DC with AC conductors?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Oh boy, I hadn't even started to read 725 before now. The definitions for class 2 and 3 circuits seem overly complex. This section is going to take some studying. [Linked Image]


#94717 - 08/14/05 08:43 AM Re: Mixing DC with AC conductors?  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Paul,

Quote
The definitions for class 2 and 3 circuits seem overly complex. This section is going to take some studying


I wish you well, you must be a gluten for punishment if you want to try to make heads or tails of 725. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#94718 - 08/14/05 05:29 PM Re: Mixing DC with AC conductors?  
Rhino  Offline
Member
Joined: Jun 2004
Posts: 24
San Diego,California,USA
I wonder wether there are some practical issues at play as well.Such as some current being imposed (through induction)on the DC circuit causing havoc with the circuits on the DC power run.
To be safe i would go with the rule of thumb of not combining one with the other.
Along the lines of even if it is permissable -should it really be done??



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