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Changing a 3-Prong to 4-Prong Dryer Plug and Cord

Updated on November 28, 2016
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Dan has been a licensed, journey level electrician for some 17 years. He has extensive experience in most areas of the electrical trade.

My Dryer Cord Has 3 Prongs but the Plug Requires 4!

So you've moved into your new home and gotten the dryer wrestled into place. The vent is hooked up, ready to go, but the cord doesn't fit the socket! Your dryer has only 3 prongs, but it needs 4 prongs to fit. What's up with this?

(If your dryer has 4 prongs and needs 3, try the one about changing a 4 prong dryer cord into a 3 prong cord).

In 1999, the National Electric Code began requiring all dryer receptacles to be the 4 prong type for increased safety, but homes built prior to that time used the older 3 prong variety. If you are moving from an older home into a newer one, you will likely find that the dryer plug won't fit.

The Best, Safest, and Cheapest Solution Is to Install a New Cord

This is not hard; most homeowners with even a few basic tools can do it. You'll need...

  • a screwdriver,
  • pliers,
  • a nut driver set,
  • and possibly a pair of wire strippers.

(Adapters are available, but they're quite expensive, and you have to make sure that the unit you purchase has a UL table which indicates that it has been tested and is safe to use and will only be used for a dryer.)

Removing the Old 3 Prong Cord

  1. UNPLUG THE DRYER BEFORE CONTINUING! If its plug doesn't fit the socket, this step shouldn't be necessary, but of course you should never attempt to work on an appliance that is plugged in. If the dryer is unplugged, there is no need to check for voltage at the dryer, although a non-contact voltage detector will accomplish this if you want to be extra safe.
  2. Pull the dryer out until you can easily work on the back.
  3. The cord should enter the dryer through some kind of connector to prevent strain on the screws where the wire terminates. Loosen any visible screws on this connector and remove the plate that covers the wire terminations. If the old wires are colored, note where the white wire ends.
  4. Unscrew the fasteners holding the wire to the terminal board and remove the wires. Pull the old cable out through the connector and save it in case you ever move into a home with a 3 hole socket.
  5. There will be a metal strap or wire fastened to the place where the white wire was, attaching to the frame of the dryer. Remove this strap or wire, and once more, save it for possible use in years to come. Take note of where this strap is screwed to the frame; one of the wires on the new cord will go there.

Removing the 3 Prong Cord and Plug

The cover plate on the back of the dryer has been removed, exposing the wire termination block.  Notice the clamp holding the wire to the dryer.
The cover plate on the back of the dryer has been removed, exposing the wire termination block. Notice the clamp holding the wire to the dryer.
Three prong cord still connected.  Note the metal piece that goes from the white wire to the frame of the dryer.
Three prong cord still connected. Note the metal piece that goes from the white wire to the frame of the dryer.
Cord removed. The metal ground strap is still connected and needs to be removed.
Cord removed. The metal ground strap is still connected and needs to be removed.

What Is the Difference Between the White and the Green Wire?

White wire: The National Electric Code (NEC) requires that (with a few specific exceptions) the white wire is the "neutral" one. In other words, it is the grounded circuit conductor wire expected to carry current and that it is grounded at the point of entry to the home (aka at the breaker panel) and nowhere else.

Green wire: The NEC requires that grounds (grounded wires that only carry electricity in a fault situation, when something goes wrong) be either green or bare of insulation, and that ONLY grounds be colored green.

Other colored wires: Any and all other colors are open for use, except that they cannot be used as either a neutral or ground. Typical 240V outlets (as a dryer is) use black and red as the "hot" wires, but any colors except white and green are legally acceptable.

How Do You Remember Which Wire Is Which?

  • Tape the wire with a label with "B," "W," and "R" written on it.
  • Make a hand-drawn diagram.
  • Take a photo with your phone (in today's world that might be the best!).
  • Commit it to memory.

Installing the New 4 Prong Cord

  1. First, make sure that you have the right new cord. A range cord (made for a cooking range) looks very similar and also has 4 prongs in about the same locations. The difference is that a dryer cord has two straight prongs and two bent ones, while a range cord has three straight prongs and one bent one. Make sure that your new cord will fit into the receptacle before installing it (do not plug into a "hot" receptacle; just hold it up next to the receptacle and verify the prongs will fit).
  2. Push the new cable through the connector. If there is no connector, one should be purchased; the most common type is a 1" romex connector that has a clamp on one side with 2 screws to tighten it and a large nut on the other. Remove the nut, place the threaded portion through the wall of the dryer, and replace the nut.
  3. With the cable through the connector, it is time to terminate (attach) the wires to the screws where the old wires came out. Black and red terminals will take the outside wires on the flat cable (or on the same colors), and the white wire (center wire on the cable) will attach to the center screw.
  4. The green wire will attach to the spot where the strap was removed from the frame of the dryer (see above). It does not go on the terminal board where the white wire is, but to the frame. It is a grounding wire for safety and is not used to supply electricity to the dryer. See the pictures for one location for the green wire; your dryer will likely be different, but in all cases the green wire is to be terminated on the frame or body of the dryer and not on one of the three screws on the terminal board.
  5. Re-attach the cover plate over the wire terminations. It is a wise precaution to turn off the breaker before plugging the dryer in, just in case something is wired wrong. With the breaker off, plug in the dryer and turn the breaker back on.
  6. If the breaker immediately trips, you have put a wire in the wrong place; turn the breaker back off and find the mistake. If it doesn't trip, turn the dryer on and make sure it operates correctly.

Installing the 4 Prong Cord and Plug

The white wire is placed on the center terminal, where it belongs.  The ground strap has been removed and the green wire attached to where it mounted on the frame of the dryer.
The white wire is placed on the center terminal, where it belongs. The ground strap has been removed and the green wire attached to where it mounted on the frame of the dryer.

Congratulations: you have successfully changed out the old 3 prong cord for a new 4 prong one that will work in your new home, and it wasn't so hard, was it? Ready to tackle putting in a new light fixture or replacing an old plugin that won't hold a cord in any more? These, too, are easy tasks that almost anyone can do.

© 2011 Dan Harmon

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    • Knowing Truth profile image

      Knowing Truth 5 years ago from Malaysia

      Thanks for sharing this useful tips and your professional knowhow.

    • wilderness profile image
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      Dan Harmon 5 years ago from Boise, Idaho

      You're welcome. As you say, this is my professional field; I'm put more than a few of these over the years, and enjoy sharing what I've learned in the process.

    • againsttheodds profile image

      againsttheodds 5 years ago

      Great tip, but if you tell everyone how to do stuff you might be out of work.

    • wilderness profile image
      Author

      Dan Harmon 5 years ago from Boise, Idaho

      :-) That's all right - in less than a year I intend to retire anyway, and I do enjoy passing on what I've picked up over the years.

    • Judi Bee profile image

      Judith Hancock 4 years ago from UK

      My husband is a not a handyman, in fact the thought of him attempting anything involving electricity scares me, so this is the sort of thing that gets left to me. I shall pin it for reference!

    • RTalloni profile image

      RTalloni 4 years ago from the short journey

      Doing this cord changeout yourself is a time saver and a dollar saver. Good stuff you have here!

    • Janis Goad profile image

      Janis Goad 4 years ago

      I might even get the courage to try this myself--I am a duffer at Do-it-yourself home repairs, but your instructions are so exact and easy to follow.

      I'm sharing this!

    • wilderness profile image
      Author

      Dan Harmon 4 years ago from Boise, Idaho

      It is indeed easy to do, and pretty hard to mess up. It can also be a time and dollar saver as most electricians will charge a minimum of $100 or so, plus parts. Then you have to schedule it and make sure you're home for the 15 minutes it will take.

      Better to do it yourself.

    • profile image

      thickalious305 4 years ago

      I just purchased a 3 prongs dryere and i have a 4 prongs outlet. this information is very handy and i praay it all goes well. Will keep you informed. Thanks for the knowledge

    • wilderness profile image
      Author

      Dan Harmon 4 years ago from Boise, Idaho

      I'm sure it will, thickalious. Just be sure that the white, neutral, wire no longer goes to the frame of the dryer and that the green one does instead.

    • profile image

      Matthew 4 years ago

      Wilderness, my dryer on the back (near the access plate) says specifically that it is a three cord dryer only. Do you think this is an issue? I just moved into a new apartment and they only have the 4 prong outlet.

    • wilderness profile image
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      Dan Harmon 4 years ago from Boise, Idaho

      No. I understand that there are few 120 volt dryers out there made for very small apartments, RV's and such but any dryer requiring the normal 220 volts can be wired following the directions give here.

      Check the nameplate on the dryer for the voltage; if it is the normal 220 volts (or anything close, such as 240 volts), follow the directions here. If it is one of those tiny dryers operating on 120 volts it should already have a plug on it that can be plugged into a regular wall socket

    • profile image

      j4nme 4 years ago

      Thanks for having this page and instructions. I was scared to do this myself, but your steps made it easy! I appreciate your post!

    • wilderness profile image
      Author

      Dan Harmon 4 years ago from Boise, Idaho

      You're more than welcome, and thanks for the post. It's always nice to hear that I've managed to help someone out.

    • profile image

      melissa 3 years ago

      Is there anyway to do this for a washer machine?? The outlet where my washer machine is located is 240volt/4 prong, but the washer has a 120volt/3prong.

    • wilderness profile image
      Author

      Dan Harmon 3 years ago from Boise, Idaho

      Yes, it can be done. Because of the danger of shock or fire, however, it should be done by a licensed electrician. They can change both the receptacle and the panel breaker into something suitable for a washer for a reasonable fee.

    • profile image

      KMAC173 3 years ago

      So I followed these directions but left the old grounding wire still attached to the frame. I then connected the 3 wires and turned on my machine (without connecting the new grounding wire) It worked perfectly....then.....I moved my dryer over and the old grounding wire touched the new grounding wire. There was a nice spark and now the dryer does not work.....is it just the cable? Or did I just create a $900 paperweight?

    • wilderness profile image
      Author

      Dan Harmon 3 years ago from Boise, Idaho

      I doubt you have seriously harmed the dryer. I'm confused, though about just what you did. You left the ground wire attached to the frame and going to the center (or white) wire on the cable. Then touched the new ground wire (that is plugged into the wall) to the old ground wire and got a spark.

      There should not have been a spark as that white wire is grounded in the breaker box anyway. Not unless you have one of the black or red wires going to that center terminal, whereupon the breaker should blow without harming the dryer. Check the breaker to see if it is blown.

      If that is the case, you are energizing the frame of the dryer; a definite safety hazard and sooner or later you WILL be shocked from it. Neither the red nor black wires should ever be grounded, either to the ground wire OR the frame of the dryer.

    • profile image

      May 22 months ago

      Hello, I had a question about the ground wire from the dryer and the ground wire to the electrical cord. If I'm understanding this correctly, I am to take the ground wire to the dryer off and push it to the side (where do I put it? The two ground wires are not allow to touch or sparks will fly?) and put the ground wire to the electrical cord on where the old used to be to replace it? I apologize, I am not very mechanical and I'm very confused.

      I have a feeling I did something wrong because the dryer is very hot to the touch and I'm afraid it may start a fire!?! When I turn it on, it works but it feels too hot? Please help :-)

    • wilderness profile image
      Author

      Dan Harmon 22 months ago from Boise, Idaho

      You should only remove the ground strap on the dryer from the terminal block. The green ground wire on the new cord will then go to the place on the frame of the dryer where that old ground strap was - NOT to the terminal block at all. You can leave the old ground strap attached to the dryer frame as long as it does not touch any of the other wires (except the new ground wire, of course). This will save it for future use in case you ever need to go back to a three wire cord.

    • profile image

      Pacific 17 months ago

      After changing this on a 6 year old Kenmore dryer that says it accepts 120 and 220/240 volts, it seems to be running a bit faster and hotter than our previous 3 prong connection at our old house. Is this normal? Thank you.

    • wilderness profile image
      Author

      Dan Harmon 17 months ago from Boise, Idaho

      No. But if wired for 120 it would do more than a"little bit" faster. Unless it used to be a 120 sweet up?

    • profile image

      Mrs Williams 8 months ago

      I have a 3 prong dyer 30amp and I only have a regular socket outlet are there Adpters that can be purchased?

    • wilderness profile image
      Author

      Dan Harmon 7 months ago from Boise, Idaho

      No. A regular socket will not carry the amperage a dryer requires.

    • profile image

      Kt 7 months ago

      Perfect, perfect, perfect....

      Articles such as yours is how I earned my nickname, Kt Villa. Merci!

      Blessings and enjoy your retirement!

    • profile image

      AngelBaby 5 months ago

      Awesome Saucesome!!!!! You Totally Rock!!!!

    • profile image

      5 months ago

      can i replace the outlet rather than the cord?

    • wilderness profile image
      Author

      Dan Harmon 5 months ago from Boise, Idaho

      If you do that you need to be aware that the home will no longer meet electrical codes and that you could be liable for any damages down the road when that house is sold. It's not a smart thing to do.

    • profile image

      Liberal123 4 months ago

      Thank you. I needed this.

    • profile image

      Gordon 2 months ago

      I need to move a 3 prong outlet two feet to accomodate a built in. I would prefer to upgrade the whole line per 250.138 but I would have to wire all the way back to the panel. The dryer itself is also 3 prong. Is it acceptable practice to extend the line per older code or should i bite the bullet and redo the whole line.?

    • wilderness profile image
      Author

      Dan Harmon 2 months ago from Boise, Idaho

      Sorry, but it is illegal to extend the 3 wire cable. Code requires a ground now, and doesn't care that your dryer doesn't. If you're going to move that outlet it will have to be re-wired all the way back to the panel, a 4 prong outlet installed and the dryer changed to a 4 prong.

      A real hassle, and expensive, but that's what is required.

    • profile image

      Julian david acosta 7 weeks ago

      Is the green cord required to be connected?

    • wilderness profile image
      Author

      Dan Harmon 7 weeks ago from Boise, Idaho

      @ Julian: Yes, the green wire is absolutely required. Not only because the law requires it but also for safety. Without that green wire there is no ground at all in the dryer. Please make sure it is used as described in this article.

    • profile image

      Bianca 6 weeks ago

      Good morning, quick question.....back in November 2015 I had my brand new LG dryer placed in my old rental home with the installers placing a 3-prong cord onto it. Fast forward to this week and with me moving into brand new build, would have to switch over to the 4-prong cord. My dilemma is that I cannot, for the life of me (nor 2 other men) get the screws holding the prongs to the back of the dryer to come off!!!! We've tried wd-40 per Home Depot's request because they refuse to come out and address it even though they were the ones that initially installed it. But nothing is working, I would hate to have to have to buy a new dryer because of these prongs. Any suggestions would be greatly appreciated?! Also, I googled and saw that Northern Tool sold a 3 and 4-prong adapter but the reviews mainly mentioned campers, is this something I could use instead of changing out the cord?!

    • wilderness profile image
      Author

      Dan Harmon 6 weeks ago from Boise, Idaho

      @Bianca: As a last resort, LG can probably supply you with a new terminal block, although that would be a shame to have to go that way because someone tightened them beyond any thing reasonable. If they are nuts on a stud (common) you might try a mechanic's socket, or possibly a nut driver might work. Beyond that and the things you've already tried I have no suggestions.

      Yes, adapters are available, although I don't like them personally. There is a link early on in this article to one from Amazon (look for a link with a little yellow "a"); although it is the wrong one for your use, the page will show ones that are correct. In your unique situation it may be the best answer, although a rather expensive one.

    • profile image

      Taylor 5 weeks ago

      Hi Dan! I got my wires all hooked up, except the ground screw will not tighten. It comes out easily. Is that normal?

    • wilderness profile image
      Author

      Dan Harmon 5 weeks ago from Boise, Idaho

      No, it is not normal to have a loose ground screw. It must be snug.

      You might try a slightly larger screw, particularly if it is of the sheet metal type. Or a screw and nut if that's feasible. You could drill a new hole in the frame somewhere and install a screw with nut. You might even splice the grounds together, adding another wire long enough to reach someplace else on the frame where there is a screw.

      But don't leave it loose.

    • profile image

      cb 3 weeks ago

      This is the easiest instructional i've come across. i just bought a dryer for a mobile home we are renting and the dryer is three prong. we have to make a run to home depot in the morning to get a 4-prong now.

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