I need to work out in the woods (building a treehouse) with up to 15 Amp tools about 200 feet from the house. Obviously I should be using battery tools, but all of my tools are wired and I’d rather not buy battery versions of all my tools. What size extension cord(s) do I need to purchase?

  • 3
    At least 12 gauge, but for 200 ft a small(2000w) generator might be almost the same price.
    – crip659
    May 30 at 10:12
  • 3
    More expensive to buy the generator on my quick look, for this distance. Far more expensive to fuel the generator than to pay your electric utility for the power.
    – Ecnerwal
    May 30 at 13:40
  • 1
    Are you in a 110V or 220V country? Acceptable voltages loses are less in 110V countries
    – CSM
    May 30 at 16:28
  • @CSM Questioner's profile says Oregon, so 120 VAC, 60 Hz, presumably.
    – Ecnerwal
    May 30 at 18:18
  • 1
    Modern battery tools store a lot of power, and you can buy more batteries. Depending on how many hours you plan to work at a stretch, batteries might be more cost-effective. You could also use a cheaper extension cord to power, say, a dewalt charger, and switch off.
    – bmargulies
    May 31 at 0:10

1 Answer 1


10 gauge (copper) would be a reasonable size - about 5% voltage drop on 120V at 15A. Be sure you are plugged into a GFCI-protected outlet.

Pricing is off topic, local, goes out of date, yadda, yadda - current 2022 USA cost in the ballpark of slightly over $100 for a 100 foot 10Ga cord, so slightly over $200 for two of them.

  • Re pricing -- just paid nearly $2per foot for 12g Romex yesterday as an example of how quick prices go up :(
    – psaxton
    May 31 at 1:02
  • 1
    Romex and extension cords are different market segments. Prices were from this morning.
    – Ecnerwal
    May 31 at 1:19
  • An outdoor outlet I think should be GFCI protected already to be up to code. But if it isn't, there's a vast selection of GFCI circuits that can be plugged in inline. Had never heard of one until I went looking. May 31 at 2:39
  • We don't know that the OP has an outdoor outlet, or if their outdoor outlet, if present, has a GFCI. Depending on age of house, neither of things were required, until they were. Not hard to find people still running cords out a window. So, always best to specify. I have one of those 6 foot heavy duty GFCI extensions, and it's a good trick to have in the bag if you find yourself faced with a dubious place to plug in.
    – Ecnerwal
    May 31 at 12:45
  • My whole house is wired with 12/2. Would plugging a 10/2 extension cord into a 12/2 fed outlet even work very well? Thinking of electricity like water, wouldn’t it be like having a 1/2” water pipe feeding a 1-1/2” pipe? The pressure would drop dramatically.
    – irrational
    May 31 at 13:11

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