UF+ LV in same conduit


Old 06-14-12, 11:38 PM
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UF+ LV in same conduit

So I was thinkin.. I just had to tunnel under a sidewalk to install a sprinkler line to the easement strip on my front yard. While I was at it, I ran a 1" PVC conduit (overkill I know but it's what I had laying around.. ) so that I could at some point down the road run power out there so I could put christmas lights in the trees without laying an extension cord across the sidewalk. It's all been filled in, and the other guy that had asked about putting a smaller PVC inside a larger for his datacom got me thinking about my pipe.. I started thinking I might want to put some low voltage lighting in the gardens and trees, and I really don't want to dig the whole thing up again (especially because using the water tunneler makes a huge mess, and since it's heavy clay it takes forever for the holes/trenches to drain).

So I had an idea.. If I were to run UF inside the conduit instead of the THWN, could I put the Malibu cable inside with it? IIRC the NEC considers cable jacketing a separator, so the insulation rating of the Malibu cable shouldn't be an issue then, right? The issue would be the Malibu could not enter a box where the UF is terminated. So what if I were to use a conduit body T right below the junction box at each end, where the Malibu enters through a gland? Would that pass muster? This is not a permit project, but I still want it to be legal.


Last edited by JerseyMatt; 06-15-12 at 01:31 AM.
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Old 06-15-12, 10:08 AM
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In my opinion, no. You could, however, use THWN conductors through the conduit and then splice them to the LV wiring outside the conduit assembly.

I stress that this is just my opinion, not a code interpretation.
Old 06-15-12, 10:54 AM
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I too say no, unless the Malibu cable has an insulation rating greater than the voltage on the UF cable.
Old 06-17-12, 08:13 PM
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The Malibu cable is rated 300v.. So since there will only be 120v in the UF, it doesn't have to match the 600v UF rating, right?
Old 06-18-12, 02:01 AM
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As long as the insulation is equal to at least the maximum circuit voltage applied to any conductor within the raceway/enclosure. So, you're fine. 300.3 (C)(1)

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