Two power sources same conduit?

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Dale001289

Senior Member
Location
Georgia
I want to run 480VAC 3ph power along with 120VAC 1ph power in the same conduit to a common piece of equipment (HVAC unit). The power sources originate from two different panel boards in a nearby electrical room. All conductors have 600V insulation. Aside from considering amp correction factors is there anything wrong with this installation from a NEC standpoint?


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bwat

EE
Location
NC
Occupation
EE
Curious. Does anybody have a preference to not doing this and would rather have them separate? I had almost this exact question come up last week and my response was something like "not a violation, but some electricians may prefer to keep them separate for ease of wire pulling and routing conduit". Basically using a tee to combine sources, rather than split a single source to multiple destinations.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
We would do this without hesitation. You would need a junction box or conduit body to combine the two raceways from different sources into one raceway.
 
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retirede

Senior Member
Location
Illinois
infinity said:
We would do this without hesitation. You would need a junction box or conduit body to combine the two raceways from different sources into one raceway.
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Right - the only reasons not to combine would be due to logistics - location of the supply panels and/or location of termination points.
 
Electromatic

Electromatic

Senior Member
Location
Virginia
Occupation
Master Electrician
You are allowed also to have a circuit from one panel/source go through another panel as long as you provide a warning label indicating the disconnecting means of the other source.
 
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jap

Senior Member
Occupation
Electrician
Electromatic said:
You are allowed also to have a circuit from one panel/source go through another panel as long as you provide a warning label indicating the disconnecting means of the other source.
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Where do you place such a warning label?

JAP>
 
J

jap

Senior Member
Occupation
Electrician
I don't get into this situation often, but, I would think the labels would be better served attached to the conductors inside the panel itself.

That way you'd know which conductors were actually the offending parties.

Oh well.

JAP>
 
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Dale001289

Senior Member
Location
Georgia
retirede said:
Right - the only reasons not to combine would be due to logistics - location of the supply panels and/or location of termination points.
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In this case the two panels are side by side and 480V disconnect and 120V receptacle are within couple feet. We plan to use Tee condulets and rigid galvanized steel conduit to route the circuits


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don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
jap said:
Come on back to the commercial side,,,, lot's less rules than residential to keep up with. :)


JAP>
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The only resi I did was a couple of apartment complexes when I was an apprentice. The bulk of my work was industrial.
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Dale001289 said:
I want to run 480VAC 3ph power along with 120VAC 1ph power in the same conduit to a common piece of equipment (HVAC unit). The power sources originate from two different panel boards in a nearby electrical room. All conductors have 600V insulation. Aside from considering amp correction factors is there anything wrong with this installation from a NEC standpoint?


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Click to expand...
infinity said:
I've never seen such a specification, but I have seen engineers dream up some crazy stuff.
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As often as not the crazy stuff is dreamed up in response to something some EC did that the engineer did not like but did not find out about in time to stop it.

I can't imagine there not being some kind of specification. Otherwise the EC would not even know what work needed doing.
 
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