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I’m planning on running 2-2-2-4 aluminum direct burial wire 30’ to a 100 amp sub panel, then another 250’ to a 50amp sub panel. The 50’ portion will be in the same trench. So it will basically go out and straight back in that 50’ of trench, before continuing on the additional 200’. Will there be any interference type issues in doing that?

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    Can you change to running the 50 amp from the main panel also to save wire? Or you need the 100 amp for more breaker space?
    – crip659
    Commented Jun 5, 2022 at 0:54
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    How is 30 feet of trench the same trench as 50 feet of trench? Anyway, Interference, no. 80-100 feet of extra wire resistance causing voltage drop, yes. More sense to run both direct and lose the extra wire length, based on the limited and conflicting information thus far presented. 2224 can only be supplied at 90A since it's a subpanel, not a residence feed.
    – Ecnerwal
    Commented Jun 5, 2022 at 0:54
  • Will they be in the same conduit? Do you understand that 2-2-2-4 is only good to 90A and needs to be breakered 90A? (usually not a problem, myself I'd just use 2-2-2-4 for all of it, since it's cheap and that will help with voltage drop on the long run). If someone told you 2-2-2-4 they're wrong, but they're wrong for a reason. Commented Jun 5, 2022 at 3:10
  • Sorry, 30’ for both, so no 50’ length. The 100a panel will have a 60a breaker feeding it. In the future all it will do is provide grid back up to a solar inverter/charge controller. They will not be in conduit, just buried. For the 250’ run I’ll only need 40a max. Pricing it out, the 2-2-2-4 was way cheaper than copper in conduit.
    – Tim
    Commented Jun 5, 2022 at 15:18
  • BTW, thank you for all the replies.
    – Tim
    Commented Jun 5, 2022 at 15:26

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There will be no problem running the lines in the same trench.

the requirements for the “feeders” to each of the sub panels being properly protected you could put in as large of a panel as you want.

The only time separation is required is from a service feeder prior to the poc and this is to prevent possible insulation failures and not cross talk to speak.

So no there won’t be problems in the trench with multiple sub feeders.

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  • Just as a sidenote -- the OP's setup will be limited to 80A due to the derates for having >3 CCCs in the same trench Commented Jun 5, 2022 at 18:03

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