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I purchased a 3-prong outlet for my dryer. The cable coming out of the breaker box has 4 wires (white, red, black, bare).

I was looking at a youtube tutorial, and it says to connect the white wire to the terminal of the outlet marked white, and the red and black to the other two terminals. The outlet has 3 terminals.

Then he says to leave the ground wire just behind the outlet. In other words, it's hanging not doing anything. But he cautions that it shouldn't be able to touch the outlet. Is this correct?

How is this grounded? My outlet box is metal, not plastic like in the video.

Some additional info related to the comments: I bought this GE washer/dryer combo about 8 years ago from Sears. The dryer came with the 3-wire prong. The installers did not change the cable in the dryer. The 3-wire prong was installed because the dryer came with a 3-wire prong.

Also, another question related to the comments: the dryer came with the 3-wire prong. This means that the dryer only has 3 cables as well. Assuming I change the cord to a 4-wire prong, where am I supposed to connect the neutral inside the dryer?

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    Take the three prong back and get the right four prong. Three prong(NEMA 10-30) was banned in the 90s for being unsafe/killing people. If the cable on the dryer has no ground wire, get a new /3 cable at the same time. You got 4 wires in the box, use them to keep you safe. About the only youtube you should trust are the Darwin Awards on how not to do electricity..
    – crip659
    Commented Aug 7 at 18:21
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    Re: "How is this grounded?" -- it's not.
    – Pete Becker
    Commented Aug 7 at 19:12
  • A modern dryer or washer/dryer should come with either a 14-30 cord/plug or no cord/plug at all. So that's strange unless it was used in some way - e.g., demo model or a return/scratch and dent (and I've bought appliances in both of those categories).
    – manassehkatz-Moving 2 Codidact
    Commented Aug 8 at 3:30
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    Although the youtube video is highly praised (!) a couple of comments below it note that the method is not correct or a code violation.
    – Wastrel
    Commented Aug 8 at 14:09

5 Answers 5

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This is an obsolete, dangerous, configuration, which gets perpetuated as follows:

  • Original 3-wire receptacle without ground (e.g., 1960s or earlier)
  • Code changed to require new circuits to use 4-wire receptacles, but grandfathered existing 3-wire receptacles
  • New dryer (because most people don't have a 50+ year-old dryer) is delivered and installers, since they are not electricians, install a 3-wire cord/plug to match the existing receptacle
  • Dryer is moved to a different house and/or sold to someone to use in a different house
  • Since the dryer already has a 3-wire cord/plug, new owner installs a 3-wire receptacle even though they have been obsolete for decades, and sometimes even if they already have a 4-wire receptacle - even though replacing the cord/plug is easier than replacing the receptacle

Any dryer made in the last few decades can be easily connected with a 3-wire (without ground) or 4-wire (with ground) cord/plug. To resolve this problem:

  • Reinstall the 4-wire receptacle (if there was one before) or install a new one (NEMA 14-30)
  • Since you have a metal box, the bare ground wire connects to the box. Some receptacles will ground automatically to the metal box, but if the instructions do not say "self-grounding" or give any other indication that they ground automatically to the metal box, add a bare wire from the receptacle ground screw to the metal box.
  • Return the 3-wire receptacle or, if it is not returnable or you don't want to bother returning it, toss it in the trash. But don't put it out as a giveaway, because nobody else should be using it either (except perhaps in the very limited situation of replacing a broken 10-30 where there is no practical ground path, but that is actually quite rare).
  • Replace the 3-wire cord/plug on the dryer with a 4-wire cord/plug.
  • Remove the neutral/ground bond (typically one wire/screw) from the dryer. To verify, check continuity from the prongs on the plug to make sure ground is not connected to neutral.
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    This is entirely too wordy. Needs a big “stop! This will kill you!” right at the beginning. Harper has it right.
    – nobody
    Commented Aug 8 at 1:57
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    Because if they didn't, people would buy them from Lowes, or even worse buy non-UL/ETL stuff from Amazon. Technically, NEMA 10-30 receptacles and cords are still allowed for repairs. Rodent chews a cord, replace the cord/plug is legitimate. Water damage to a receptacle, replace is legitimate. But I'd venture to guess that the vast majority of 10-30 cord/plugs sold since 1996 are "new dryer, but I have a 10-30 receptacle so using a 10-30 cord/plug is the cheap/easy thing to do". And probably most, but not as much of a vast majority, of 10-30 receptacles are either
    – manassehkatz-Moving 2 Codidact
    Commented Aug 8 at 3:17
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    "I am moving my dryer to another location in the house so I need a new receptacle to match the existing dryer cord/plug" or the even worse "I just got a used dryer with a 10-30 cord/plug already attached so I'll replace the 14-30 receptacle with a 10-30 receptacle" (that last one is really, really bad and sounds like what is happening here).
    – manassehkatz-Moving 2 Codidact
    Commented Aug 8 at 3:19
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    So now I am really confused. You bought the washer/dryer 8 years ago. So why are you replacing the receptacle now? Model # of the washer/dryer would be helpful.
    – manassehkatz-Moving 2 Codidact
    Commented Aug 8 at 3:31
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    @rbhat The only unique perspective I can offer here is, don't let the apartment management find out you're dorking around with their receptacles.
    – smitelli
    Commented Aug 8 at 13:39
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Don't change the dryer socket. Change the dryer cord. They are designed to be easy to change and the dryer instructions (google the model number) or the labeling will show what to do with the ground strap.

It is illegal to install that socket and has been since 1965 for everything but dryers (1996 for those). That socket does not have a ground, and that's obviously dangerous.

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  • If they're illegal, then why does Home Depot sell these outlets? And why does Home Depot also sell the 3-wire dryer cord?
    – rbhat
    Commented Aug 8 at 3:10
  • I understand the comment, but I don't understand why home depot sells something that should not be used.
    – rbhat
    Commented Aug 8 at 3:14
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    @rbhat why does Temu, Wish, eBay and Amazon Marketplace sell dangerous uncertified crud as like 90% of their catalog? The answer is, NEMA 10 sockets are sold for like-for-like replacement of broken sockets. NEMA 10 cords are sold for when you move into a house that legally had a 3-prong outlet installed pre-1996. What are you honestly expecting, a police/nanny state? That is not how America works. The onus is on you to know what you're doing and be responsible.
    – Harper - Reinstate Monica
    Commented Aug 8 at 4:47
  • I'm only chiming in form the other side of the pond, absolutely no interest in it either way but wouldn't it be still wise to require that to be visible on the packaging in a prominent way? One wouldn't want to ban HD and others from selling it, for sure, but still, people could be informed that it's for replacement of existing items only and not to replace other types of outlets with. I don't think this would be tantamount to a nanny state.
    – Gábor
    Commented Aug 10 at 10:11
  • @Gábor I totally agree. However our products are already inundated with warning labels, so a labeling law/reg would need to require it be the only or the dominant warning label.
    – Harper - Reinstate Monica
    Commented Aug 11 at 23:22
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The dryer came with the 3-wire prong

If that's true, whoever sold it to you was criminally negligent. Three-wire dryer connections have been obsolete and wrong for many, many years. These days (and for many years), everyone should be using four-wire dryer connections for everything. There is a narrow, narrow backwards-compatibility "grandfathering" exception, but I don't believe it applies to you, and even if it does apply it is (IMO) such a bad idea that you should not be using it anyway.

Then he says to leave the ground wire just behind the outlet. In other words, it's hanging not doing anything. Is this correct?

It is blatantly incorrect for your case.

The fundamental rule in safe, modern electrical systems is that every piece of metal that does not carry current should be grounded. You said you have a metal box, so: the ground wire must be, at least, connected to the box. But also: the metal frame of the dryer must be grounded, too, and this is precisely why you need a proper four-prong grounded outlet and a grounded, four-wire cord.

the dryer came with the 3-wire prong. This means that the dryer only has 3 cables as well. Assuming I change the cord to a 4-wire prong, where am I supposed to connect the neutral inside the dryer?

The dryer instructions explain this. The dryer has four connections internally, so connecting a four-wire cable is perfectly straightforward. There's a kludge (likely involving a temporary jumper) for connecting a three-wire cable. You do not want to use this kludge. Manassehkatz's answer has more on this, as does this other question.

What I don't seem to understand is why Home Depot sells these 3-prong outlets and the 3-wire dryer cords.

Two reasons:

  1. For the narrow, narrow backwards-compatibility "grandfathering" exception I mentioned.

  2. So that stupid people can do stupid and dangerous things.

As I said, I believe the grandfathering exception does not apply to you (and in my opinion you should not make use of it even if it does apply). And, needless to say, I think we both agree you don't want to be one of the stupid people in #2!

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    To confirm that the exception doesn't apply is a pretty easy read, the Code section starts "For existing branch-circuit installations only, if an equipment grounding conductor is not present in the outlet or junction box..." up.codes/viewer/colorado/nfpa-70-2023/chapter/2/…
    – NoSparksPlease
    Commented Aug 9 at 0:11
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    Note that, even in some kind of post-apocalyptic scenario where getting the correct cord for the dryer was impossible, the best solution would still not be to just leave the ground wire loose behind the receptacle. You'd at least want to fasten it to the inside of the box, and preferably also jumper it out to the frame of the dryer for a decent ground.
    – Perkins
    Commented Aug 9 at 17:52
  • "It is blatantly incorrect for your case." Then please, somebody with the necessary background and knowledge do the world a favor and go to that YT video and describe the problem in no uncertain terms. People seem to praise the video in the comments. You could even threaten the poster with contacting YT for endangering people's lives or whatever... :-)
    – Gábor
    Commented Aug 10 at 10:24
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As others have said, you should replace the cord from a 3-prong to a 4-prong. Using a 4-prong receptacle is required for new installations and is safer. If you've got the 4 wires coming into the box, use them all.

Assuming I change the cord to a 4-wire prong, where am I supposed to connect the neutral inside the dryer?

Look up your dryer's installation manual; instructions to connect 3-wire and 4-wire cords should be there. For example, here's an instruction manual from a 2005ish Sears dryer model that shows how to connect a 4-wire plug:

instructions from PDF

Note that this is from a dryer that is almost 10 years older than yours. Yours may have 4 slightly different connection points, but you'll have to check it yourself and see what the manual recommends. Either way, dryers have had support for 4-prong cords since well before you bought this one.

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There was this comment under another answer

If they're illegal, then why does Home Depot sell these outlets? And why does Home Depot also sell the 3-wire dryer cord?

I have a house built in 1975. They ran aluminum 6-gauge three-line cable to the receptacle. If the receptacle breaks, I need some way to replace it in a way that does not imply it is grounded. This is why you can still buy NEMA 10-30R receptacles and plugs. It's also why no new electric dryers come with the plug attached. The cost of replacing that cable would be pretty steep.

As mentioned by the other answers, if you have 4-line cable you really should be using a 14-30 outlet and plug, which affords you ground so you reduce the chances of electrical shock.

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