I have a 2-2-2-4 AL SER cable from my main panel, up, and in a straight line, perpendicular and through the overhead joists of my unfinished basement. I am feeding it through the last joist into my attached garage, when I realize my SER cable is going to be about 6 feet short to make it to my new subpanel. What are my options?

  • What actual load do you anticipate on the subpanel? That may affect available options. Commented Jan 6, 2023 at 5:26

1 Answer 1

  1. Pull the cable out and replace with a longer cable. If your original cable was a standard size (100' and you needed 106') then you might be able to return it for credit. If it was purchased by the foot, you won't get so much back.
  2. Move the subpanel. Only practical if (a) you haven't started wiring up the subpanel and (b) the end of the cable is in a place that is legal for a subpanel - i.e., has a 30" x 36" space in front of it that can be kept clear.
  3. Put in a big junction box and use Polaris connectors (or similar) to connect the wires to a 6' length of cable. This is trivially simple, but the Polaris connectors are not cheap.
  4. Put in a disconnect box. That will take care of the hot wires (and neutral if you can get a 3-wire disconnect) just leaving ground and neutral to be spliced with polaris connectors inside the box. The problem is that disconnect boxes are dirt cheap up to 60A and then essentially go up to subpanel price or higher. And you can't just use a cheap 100A subpanel because subpanels need clear working space.
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    Disconnect as possibly cheaper splice. Very good. Fair chance a 60A disconnect will take #2 wire, and then the breaker can be downsized to 60A easy peasy. However this won't allow "bonkers speed" EV charging, bummer! Commented Jan 6, 2023 at 5:23
  • At least one disconnect I looked at would only go to 4 AWG, but there are others. You're right about the size - I'm assuming 2/2/2/4 = 90A. But it could be for a 60A panel and 2/2/2/4 = good price so why not. Commented Jan 6, 2023 at 5:25
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    @KMJ Can a disconnect be mounted to one of the overhead basement joists?
    – user149104
    Commented Jan 6, 2023 at 16:11
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    Polaris and Ilsco brand "multi tap connectors" are priced like they're special but there are other brands that are more reasonable. Morris #97116 is coming in around US$17 for two-port, insulated, 2/0-6 gauge. Four of those plus a box compares against the alternatives pretty well IMHO.
    – Greg Hill
    Commented Jan 6, 2023 at 17:40
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    @manassehkatz-Moving2Codidact Found what I need to do: "When transposing cable size into raceway size in 314.28(A)(1) and (A)(2), the minimum metric designator (trade size) raceway required for the number and size of conductors in the cable shall be used".
    – user149104
    Commented Jan 8, 2023 at 21:47

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