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My laundry room dryer outlet is currently wired with a 50 amp 3-prong outlet, but has a 30-amp breaker on the main panel. I've been using the dryer in this outlet just fine for a year after moving in with a 3-prong 50 amp cord I connected to the dryer. My understanding is that these are typically used just for electric oven ranges. (Example of current outlet here: https://www.homedepot.com/p/Leviton-50-Amp-125-250-Volt-Shallow-Flush-Mounted-Single-Outlet-Black-R30-05206-S10/302480499)

EDIT: Based on updated photos, looks like I have L1, L2, N, and G to wire into a new 30a 4-prong outlet. In my exisitng outlet ground and neutral are wired together.

UPDATED: added 2 photos of wiring on existing 50a 3-prong outlet: view #1 of wiring view #2 of wiring

Is it okay to leave this in place? I know this no longer the practice for new work. I am about to buy a longer cord for my dryer, and was going to buy the same 50 amp 3 prong cord. The price difference for the 50 amp cord is minimal, so I'd rather leave this outlet in place.

Or, should I just replace this outlet with a new 30 amp outlet? If I do use a new 30 amp outlet instead, should I be using a 3 or 4 prong style? Is the dryer dependent, and wiring dependent? If I do replace the 50a outlet, it seems like I should be replacing the 3-prong outlet at 50 amps with a new 3-prong outlet at 30 amps.

Example of 30 3-prong I would purchase: https://www.homedepot.com/p/Leviton-30-Amp-125-Volt-250-Volt-Shallow-Single-Flush-Mounted-Outlet-Black-R30-05207-S10/302480849

Or 4-prong: https://www.homedepot.com/p/Leviton-30-Amp-Industrial-Flush-Mount-Shallow-Single-Outlet-Black-R10-00278-S00/300324233

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  • See diy.stackexchange.com/q/236775/18078 for background so we don't end up reposting all of that, though it's not actually a "duplicate" as such.
    – Ecnerwal
    Sep 6, 2022 at 16:15
  • Sorry, folks, didn't realize I should be looking at a different site, and never searched for answers at the DIY site.
    – jhickok
    Sep 6, 2022 at 17:30
  • For anybody following, thanks for the confirmation... I knew it was wrong, just not HOW wrong.
    – jhickok
    Sep 7, 2022 at 13:44
  • I want re-emphasize that it is very important to make sure you follow the dryer maker's instructions for installing the 4 wire plug (Specifically they will have to remove some strap or screw that connects the grounded case to the neutral pin). I know Harper mentioned it, but if you fail to remove the drier side neutral ground connection, you have failed to improve safety and left a code violation. Sep 12, 2022 at 18:40
  • Thanks Kevin. Yes, they make it clear in their instructions. I removed the neutral dryer ground, as they describe, and connected it the middle neutral post, as they describe. Then I connected the green ground from the cord to the ground on the washer that was freed up, as they describe.
    – jhickok
    Sep 13, 2022 at 21:11

4 Answers 4

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New, 30A 4-wire 4-prong (NEMA14-30) is the right, safe, and correct thing to do.

10-30 and 10-50 outlets were (finally) banned in new construction nearly 3 decades ago. Every now and again they manage to kill people. They can still be purchased "for repair only" of existing circuits with the wrong wiring, but it's really past time for them to go, and some folks do misapply them for uses other than that.

How easy or hard that is will depend on what the wiring to the improper 10-50 you have is. (So, turn off the breaker, and pull it out and edit in pictures of that.) The dryer will also need to be changed to remove the neutral-ground bond, but that is a simple change when you are replacing the cord.

Edit post picture: Incredibly easy to do this right with the wiring you have (though you'll have to check that the other end is wired correctly, and correct it if it isn't, to be sure.) So some idiot deliberately chose to do it wrong on this house in the past. You have a 4-wire cable with separate Neutral and Ground conductors. Get a NEMA 14-30 R and a 14-30P dryer cord, and check the wire connections at the far end of the cable (in the breaker box that feeds this.)

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  • Ok, so sounds like the current wiring is the big question. I'll try and find some time soon to pull that outlet off and photograph. Thanks!
    – jhickok
    Sep 6, 2022 at 17:18
  • I think I've seen reports of 2 kills in the same month. Both children who crawled behind the dryer to get something, and as such were confined and could not jump away when they were shocked. Scary. All it takes is a simple wire break, not even a miswiring (though it's reported as miswiring). Sep 6, 2022 at 20:43
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    Yikes! I finally replaced mine when I got my heavy up done (well, 99% done - Pepco still has to move the meter to the new wires outside - but all the inside work is done, 42 space CH panel, generator inlet and interlock, messed up (didn't know it until taking apart the old fuse panel) MWBC fixed, new ground wire & rod, and passed inspection) since the dryer receptacle had to be redone anyway (it was blocking the new panel location). I could/should have done it along time ago myself but it was never a priority, plus I was always a little scared of the 1957 fuse boxes. Sep 6, 2022 at 22:07
  • "So some idiot deliberately chose to do it wrong on this house in the past." Probably did the same thing that the "idiot" who lived in my house did -- wanted to use a dryer that didn't fit in the receptacle, so they changed the receptacle instead of the appliance cord.
    – smitelli
    Sep 8, 2022 at 3:08
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The code violations here are legion. The installation actually has a 4-wire cable so there's no earthly reason not to use the correct NEMA 14-30 socket.

The last guy was an incompetent DIYer who thought neutral and ground are the same thing. That is wrong. (people think that because they see them bonded at the main panel). By tying neutral and ground here, the house now has 2 neutral-ground bonds, causing all sorts of potential problems.

You should search the house for any other illegal idiocy.

On dryers and ranges, 3-prong connections use a compromise technique where ground is bootlegged from neutral. Of course that's illegal anywhere else, but the rationale in 1966 was that dryer connections are rarely disturbed so the neutral wire isn't likely to fail. If the neutral did fail, it would energize the chassis of the dryer/oven!

The plan in 1966 was to only allow cable types going obsolete (to allow use of remaining stocks) and going forward require "/3 w/ground" type cable for all installations, even with 3-prong sockets. That way people could easily upgrade to 4-prong sockets.

By 1996, the fatality numbers were rolling in, so they banned the NEMA 10 sockets altogether. This work looks newer than 1996 and was clearly done without a permit.

  • Install a NEMA 14-30 socket.
  • Then convert the dryer plug to NEMA 14-30 using the manufacturer instructions. Those instructions will say how to remove the bootleg ground strap. Very important, that!
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    Thanks. I already have found some other suspect electrical work in this home.
    – jhickok
    Sep 6, 2022 at 21:43
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    No earthly reason...
    – Neil
    Sep 7, 2022 at 7:31
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North America Dryer outlets

The 3-wire 50A 125/250-Volt is still sold but obsolete for dryers since they are ungrounded, not for Dryer use. They only have L1, L2 & N connections.

enter image description here

The breaker only serves to protect the wire and unit. The 30A breaker is correct and the dryer uses (L1)120+(L2)120=240 for < 30A heat and may use 120 V + N for electronics. Ground is used for chassis.

NEMA 14 30A 4 wire outlet is correct

enter image description here

Check N and chassis ground are isolated in dryer.

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Looking at the photos, you already have the wiring for a 4 prong outlet: two hots, a neutral and a ground. But someone has botched it by connecting both the neutral and ground to the same terminal. You are not supposed to connect neutral to ground anywhere except at the origin of the supply.

So get the correct 4 prong soecket, and separate the neutral and ground to the appropriate terminals.

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    I'm no expert by any means, but this is exactly what I was thinking. Thanks. I already went and bought the appropriate 4-prong receptacle and dryer cord.
    – jhickok
    Sep 6, 2022 at 21:38

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