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I have installed a new sub-panel in our barn. We do not need a lot of power so I only ran 8/2 copper. My intention was to make the sub-panel 120v only by using a jumper for the second hot lug. Now I’m reading that this is bad! Thoughts on doing it this way? The cable has been run and buried so I’m kinda stuck. Any help would be appreciated.

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It would most likely be a code violation to put the feed hot into one lug, and also put a jumper to the other lug in with it. You must follow the instructions provided with listed equipment, and it is exceedingly unlikely that your panel lugs allow two wires in one lug.

Making two #8 pigtails, connecting them to the feed hot with an appropriately-sized wire nut (or other listed splicing device), and putting one in each panel lug would be fine.

Burying 8/2 copper with ground wasn't illegal (as long it was cable rated for burial and covered to the required depth), but it wasn't a good choice. For the same price as 8/2 copper, you could have purchased much larger /3 with ground aluminum that would have given you the potential to do 240V and much higher amperage in the future.

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  • they don't make wire nuts that big, it would have to be some other sort of splice.
    – Jasen
    Oct 20, 2022 at 1:54
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    The do make wire nuts listed for 3 #8 wires (see diy.stackexchange.com/questions/156651/…), but the important point is the splice has to be done with a listed device - not on the input lug.
    – nobody
    Oct 20, 2022 at 2:02
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    @Jasen Yes, they do. 3 x 8 AWG can go in a homedepot.com/p/… Oct 20, 2022 at 2:03
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    Pigtails sound like a much better option. I was thinking the same until someone told me just to “jump” over to the other hot lug from the one hot wire coming in. As long as I label it 120v sounds like it should be ok. And you’re right I ordered #6 Al wire back in September but it never showed and the job had to be done with what I could get. Bad decision…
    – Brian
    Oct 20, 2022 at 2:55
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    @Brian because #2 is commodity wire very widely used so it is at a pricing "sweet spot". So #4AL is not cheaper, and #6AL is barely cheaper and a few AHJs don't like it. As such, people just go straight for #2 for almost all feeders 30-90A. You'd have had no trouble finding #2. Also, always buy wires locally at electrical supply houses - they have good stock of aluminum, unlike big box stores which are better avoided. Oct 20, 2022 at 3:10
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Its not bad. Not done frequently, but it's OK. You'll want to label the cover 120v only, so if anyone else works on it or you sell, they'll know. Assuming the barn is a detached structure, you'll need to follow the usual rules for a sub-panel: Locally installed ground rods and isolating the neutral from the ground in the sub. Hopefully the 8/2 is 8/2 with ground. You'll connect the grounds from the grounding rods to the ground bus bar in the sub and the ground from the 8/2 to the ground bar as well.

Bottom line is it's OK to do.

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  • Who is upvoting this? I seriously doubt any listed panel allows putting two wires under one feed lug (as the OP implies they intend to do with the "jumper" wording). That would be a clear code violation.
    – nobody
    Oct 20, 2022 at 1:46
  • @nobody The "jumper" part is trivial - with 8 AWG, just add two pigtails from the incoming hot wire and connect one to each lug. Oct 20, 2022 at 1:55
  • Correcting it is simple, yes, but given that the question if anything is wrong with the setup, a useful answer needs to clearly spell out what is wrong and how to fix it. Just saying "it's OK" is not helpful. This answer implies that running a jumper from one lug to another is OK, which it almost certainly is not.
    – nobody
    Oct 20, 2022 at 2:09
  • @nobody George is probably not addressing that. There's more than one thing to discuss here. Oct 20, 2022 at 3:20
  • @nobody The OP specifically asked if it was ok or a bad idea, I responded directly to the question, he didn't ask how to do it, he had that part figured out already. I maintain there is no issue with jumpering the two hots lugs and turn it into a 120v only panel. Oct 20, 2022 at 4:00
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It's a code violation in most cases to run two wires in the same lug so a jumper from the breaker/bus hot phase to the other position on the main breaker/bus would be a no no. Connecting only one leg would be OK but you'd only be able to use every other space. You could also pigtail 2 #8 to the incoming #8 and run each one to a lug on the breaker/bus. You have really limited your potential use of the panel by not running the 120/240 volt service.

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    Just wondering why the DV?
    – JACK
    Oct 20, 2022 at 1:52
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    A useful answer would say how to correct the problem.
    – nobody
    Oct 20, 2022 at 2:09
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    @nobody I thought I did that. Remove the jumper and just use one side since he didn't need a lot of power. Will edit in pigtailing.
    – JACK
    Oct 20, 2022 at 2:17
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    @GeorgeAnderson It is not a general code violation. But code requires following the instructions. Which typically allow 2, or even 3 in some cases, wires per connection for ground, usually 1 per neutral and almost always 1 per main lug. It is possible to design a lug that can handle multiple wires, but since that would not be automatic and since the vast majority of time it is unnecessary, the manufacturer's don't bother. Oct 20, 2022 at 21:02
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    I think the question of whether or not it is technically a code violation is down to the panel manufacturer and the lug design. If the lugs were intended for >= 1 cable, it would have been specified at the time of UL testing/listing. If not, it would be a violation of 110.3: approved, labeled, & listed.
    – Chris O
    Oct 20, 2022 at 21:17

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