So I have this aluminum underground feeder that is 110 ft that was supposed to be 115ft. Can you extend this line by splicing or creating a junction box or am I screwed and have to get new wire? The two hots are 4AWG, neutral is 2AWG, and ground is #4.

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    Can you prove you ordered 115ft? This is a major screw-up for the electrical supply. They need to make it right. Oct 23, 2019 at 22:26
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    I agree with @ Harper it is rare they are off but it happens and if they mis measured they will usually supply the underground splice kit. Note many brands have foot markings on the wire this is what they will want to verify.
    – Ed Beal
    Oct 23, 2019 at 23:31
  • I take it this is a direct bury multiplex (mobile home feeder/tri-rated USE quadplex) cable, no? Oct 24, 2019 at 0:01
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    Yeah I meant #2 for hots and #4 for neutral and copper D ground. This its direct burial Black Stranded AL MHF USE-2 Cable. I am looking into finding the right splice kit for this.
    – user108380
    Oct 24, 2019 at 2:06
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    plenty of repair kits on the market (usually to deal with the aftermath of underground cabling's natural predator: the mini-backhoe) but its a shame to use those for new installations
    – Borgh
    Oct 24, 2019 at 11:12

1 Answer 1


You can make a splice in an appropriately sized junction box indoors. Given the large size of the wire, there will be certain minimum box size specs. The box will be long and thin if you do nose-tail connections of the wires. The electrical supply house should be able to help you with box size.

The type of splice used is called a Polaris. Take care to torque it to spec. Select Polaris connectors just large enough for your wires, so the insulation fits the connector tightly.

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