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#94711 - 08/10/05 03:33 AM Mixing DC with AC conductors?
MikeW Offline
Member
Registered: 06/03/02
Posts: 39
Loc: Michigan
Does the NEC allow 24vdc wires to be run in the same conduit with 120vac conductors?

What code section(s)?

thanks
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#94712 - 08/10/05 04:21 AM Re: Mixing DC with AC conductors?
resqcapt19 Offline
Member
Registered: 11/10/00
Posts: 2209
Loc: IL
Mike,
Look at 300.3(C)(1), but make sure that you read the FPN that follows that section.
Don
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#94713 - 08/10/05 09:44 AM Re: Mixing DC with AC conductors?
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9066
Loc: 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.
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Greg Fretwell
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#94714 - 08/13/05 05:17 AM Re: Mixing DC with AC conductors?
pauluk Offline
Member
Registered: 08/11/01
Posts: 7693
Loc: 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.,
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#94715 - 08/13/05 06:28 PM Re: Mixing DC with AC conductors?
resqcapt19 Offline
Member
Registered: 11/10/00
Posts: 2209
Loc: 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
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#94716 - 08/14/05 05:12 AM Re: Mixing DC with AC conductors?
pauluk Offline
Member
Registered: 08/11/01
Posts: 7693
Loc: 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.
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#94717 - 08/14/05 05:43 AM Re: Mixing DC with AC conductors?
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4343
Loc: 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.

Bob
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#94718 - 08/14/05 02:29 PM Re: Mixing DC with AC conductors?
Rhino Offline
Member
Registered: 06/28/04
Posts: 24
Loc: 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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