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Mixing DC with AC conductors? #94711 08/10/05 06:33 AM
Joined: Jun 2002
Posts: 35
M
MikeW Offline OP
Member
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
Re: Mixing DC with AC conductors? #94712 08/10/05 07:21 AM
Joined: Nov 2000
Posts: 2,148
R
resqcapt19 Offline
Member
Mike,
Look at 300.3(C)(1), but make sure that you read the FPN that follows that section.
Don


Don(resqcapt19)
Re: Mixing DC with AC conductors? #94713 08/10/05 12:44 PM
Joined: Jul 2004
Posts: 9,513
G
gfretwell Online Content
Member
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
Re: Mixing DC with AC conductors? #94714 08/13/05 08:17 AM
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Posts: 7,520
P
pauluk Offline
Member
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.,

Re: Mixing DC with AC conductors? #94715 08/13/05 09:28 PM
Joined: Nov 2000
Posts: 2,148
R
resqcapt19 Offline
Member
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)
Re: Mixing DC with AC conductors? #94716 08/14/05 08:12 AM
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Posts: 7,520
P
pauluk Offline
Member
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]

Re: Mixing DC with AC conductors? #94717 08/14/05 08:43 AM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
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
Re: Mixing DC with AC conductors? #94718 08/14/05 05:29 PM
Joined: Jun 2004
Posts: 24
R
Rhino Offline
Member
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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