(Still learning) Just noticed that our electrician had used 8-gauge wire for a 240v 20amp circuit. Why would he do this? Couldn't he have just used 12 gauge? Is there a method to the madness?

  • Are you sure about all that? Maybe post a photo as a sanity check.
    – isherwood
    Commented Oct 19, 2018 at 19:08
  • You need to add some more detail. What is special or distinguishing about this circuit as compared to others? You can hit the edit button below your keywords to edit in more info. Do not post an answer. Commented Oct 19, 2018 at 20:53
  • Did you get a satisfactory answer? If so, please give a check-mark to the answer that helped you the most, or write up your own answer explaining what you did to get it fixed and give yourself a check mark. That will help others with this kind of problem know that this has a resolution and is a good place to look for their answer
    – FreeMan
    Commented Jul 30, 2020 at 14:14

1 Answer 1


There can be many reasons for using a larger than normal wire, including but not limited to.

  1. The person desinging the installation thinks that the breaker rating may need to be increased in the future.
  2. The circuit is unusually long and the larger wire is needed for volt drop reasons.
  3. Thermal insualtion or grouping concerns require the cable to be de-rated.
  4. The electrican was in a hurry and simply didn't have any smaller cable of the appropriate type on-hand.
  5. Someone simply made a mistake.

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