I went into home depot to get an extension cord that was 5 foot 14 gauge. I couldn't find anything that small in that gauge and I asked the employee for his recommendation. He told me to just make my own and he proceeded to cut me 5 feet of 12 gauge wire and hands me a female and Male plug.

I've wired outlets and Ethernet before so I'm not too worried about it I just want to confirm some things before I do it so I don't blow the house up.

Green is ground, Black is hot, White is neutral.

Black goes to the gold contact and white to the silver contact. Green meeting green. Is this correct?

  • Before I answer, I need a critical piece of information: What will this extension cord be used for?
    – Tyler M
    Mar 5, 2020 at 19:13
  • @TylerM It's for a garage door opener. Mar 5, 2020 at 19:21
  • 2
    Making a cord isn't a good idea. It won't be UL listed and insurance companies don't like hack jobs. Better of moving the outlet closer to the opener and just plug it in.
    – JACK
    Mar 5, 2020 at 20:59
  • 1
    @JACK - or use a UL listed cord and try not to be so OCD about length. If we're going to be OCD about something, let's make it safety. Which means, not making your own extension cords.
    – Mazura
    Mar 6, 2020 at 3:36
  • 2
    If it's possible to get a six-foot or ten-foot cord, I would just do that instead of going through the whole ordeal of making my own cord. If it's got extra dangle in it and you want it to look neat, you can just put a coil in it and secure it with a cable-tie. Mar 6, 2020 at 3:44

3 Answers 3


Yes, building your own cords is fine, as long as you use UL-listed plugs and sockets, and use them correctly according to instructions and labeling, e.g. with right size cable and using the strain reliefs. Make sure they gave you well-fitting ones.

And you need to use correct cordage, one of several types including SJOOW (off the top of my head). It is always stranded wire. UL-listed plugs aren't even listed for solid wire.

I don't agree with their advice of build up both ends out of line cord; I prefer to start with a pre-made extension cord and cut one end off, leaving one end a factory end. Factory plugs are more durable than field-fitted plugs, or, you can preserve a triple socket end.

  • 1
    Use the right type of wire, too -- cordage (SO, SJ, etc), not building wiring (cable such as NM/Romex, loose conductors, etc).
    – Greg Hill
    Mar 5, 2020 at 22:30
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    Yeah, building wiring (like Romex) is exclusively designed to go inside walls. It isn't designed to withstand repeated flexing (as in an extension cord) -- it usually isn't stranded, and if it is, the insulation is not designed for constant abrasion against the conductors. Mar 6, 2020 at 3:43

The standard in the US is:

  • BLACK WIRE - GOLD SCREW - HOT (the 'live' wire)
  • WHITE WIRE - SILVER SCREW - NEUTRAL (the regular 'return path')
  • GREEN WIRE - GREEN SCREW - GROUND (the 'save my skin in an accident' backup path)

The smaller of the two spade terminals is the HOT and the bigger is NEUTRAL. The round plug is GROUND.

Remember, looking face-on at the female end, HOT is on the right, but looking face-on at the male end, HOT is on the left.

Here are the hookups for the female end: enter image description here

  • Thank you. The leviton plugs I got have the different screws in the back but I will make sure they align with the diagram. Thank you very much Mar 5, 2020 at 19:37
  • No problem. Personally, I would just return the wire and buy an extension cord - less stress, less struggle, maybe a little less money too.
    – Tyler M
    Mar 5, 2020 at 20:13
  • They probably won't take the wire back if they cut it for him.
    – JACK
    Mar 5, 2020 at 21:02
  • 1
    Making a cord isn't a good idea. It won't be UL listed and insurance companies don't like hack jobs. Better of moving the outlet closer to the opener and just plug it in.
    – JACK
    Mar 5, 2020 at 21:03
  • 1
    Happy outlet man is winking at you with his left eye, the hot one.
    – Trout
    Mar 6, 2020 at 1:22

It doesn't have to be from this manufacturer, but they all look just like this: UL-listed, 3-prong, flat, grey, heavy-duty extension cord. Yes, it's 9 feet long; deal with it. Use some zip-ties. Your HD has these in stock, or someone should be fired.

enter image description here


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