I have an extension cord that is 15ft and it is a 16/3. I have a 20ft of 12/2 cable. Can I use it to extend the extension cord for about 5 more feet?

The devices connected to the extension cord will still be a max of 13 amps. I just want to use the 12/2 so that I won't buy new cable.

I am thinking about cutting my extension cord (16/3) half way so that I can still use the end outlets-plug. If I can merge them, do I connect black and red from 16/3 to black on 12/2 and then black split to red and black again (see diagram)?

                            --red----              --red 16/3---
Flat Plug -- 10ft of 16/3 --         --12/2 black--              ----extension outlet
                            --black--              --black 16/3--

neutrals and ground will be connected accordingly.

  • 3
    No, a spliced extension cord is a dangerous collection of parts. The only safe answer is to get another cord, that will reach the full distance.
    – Some Guy
    Mar 28, 2015 at 21:28
  • 3
    Or get some plug ends and turn that length of 12/2 into an extension cord. Mar 28, 2015 at 21:49
  • So, is it a problem of mixing different types of cables? What if I were to buy exactly the same 16/3 to extend the original. I can't see the danger of having a spliced connection up high, taped and insulated. Of course buying the plug ends does sound appealing too.
    – Michael
    Mar 29, 2015 at 4:59

1 Answer 1


Don't splice it -- you can either just buy the appropriate extension cord for the job, or use a field-installed plug + cable-mount receptacle to convert the length of 12/2 W/G into an extension cord.

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