I was wondering if I could run 120v wires inside in a larger conduit that has higher voltage wires 240v, in a smaller piece of conduit?

The reason I ask is that I have a manufactured home and when they installed the 240v wiring coming from the meter it is run under the house in the crawlspace. It's not in conduit untill it enters the bottom of the electrical panel. When the water pump (120v) was installed they just ran it into the conduit with the 240v wiring.

I know for certain you can't run low and high voltage in the same conduit, but I thought that if I ran a 1/2" conduit inside the 2" for the 120v that would rectify the violation.

  • I believe that adding conduit inside conduit impact the fill of the outer conduit, and that you may run foul of that code long before you run into problems with 120v & 240v cable or wire inside a single piece of conduit. Also, can you specify whether you have "wires" (individual strands of wire, each insulated and colored to indicate whether it's ground (bare/green), neutral (white/grey) or hot (red/black/other), or if you have "cable" (2 or more "wires" inside an additional protective jacket). (Note: colors based on US standards, YMMV)
    – FreeMan
    Sep 25 '20 at 11:38
  • 1
    You don't have any "low voltage" and you don't have any need to separate the wires you are discussing.
    – Ecnerwal
    Sep 25 '20 at 12:35

I assume you are in the USA for this answer.

120 volt circuits are not considered “low voltage”. Low voltage means 60 volts (I believe) or lower. 120 volts and 240 volts are the same voltage class and it is perfectly fine to run both of them in the same conduit.

Besides, in the USA, 240 volt circuits are simply two legs of 120 volts in opposite phase. While you have 240 hot-to-hot, it’s still 120 volts hot-to-ground, just like a 120 circuit.

Edit: typo

  • I think low voltage is typically considered 50V actually, which is part of why 48VDC equipment is so common.
    – Nate S.
    Sep 25 '20 at 18:23
  • @NateS. You may be right. I'm not a professional sparky and a quick Google search is inconclusive.
    – DoxyLover
    Sep 25 '20 at 18:35
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    Yeah, it's poorly defined in the NEC -- different sections say different things. I think under 50V is the most commonly used value though. See here for some more info: electrician2.com/weltrain05/lpage103.html
    – Nate S.
    Sep 25 '20 at 18:39

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