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Can I wire the four wire cord to a three wire plug so it works for the three prong outlet?

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  • What is your dryer model and brand? It can be done depending on the model
    – Ed Beal
    Mar 18 '20 at 22:12
  • Can you post photos of the inside of the receptacle box please? Mar 18 '20 at 23:19
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Your dryer wants the modern, safe NEMA 14-30 recep.

Your house has the obsolete, dangerous NEMA 10-30. If the neutral wire has a common problem, it will electrify the chassis of the dryer.

So you can, but you shouldn't. Here are your options:

LUCKY: There's a 4-wire cable underneath that 3-prong outlet ($15)

Turn the breaker off. Unscrew the receptacle and go see.

If you see either a ground wire, or metal conduit going back to the service panel, you're in luck. You can simply change the receptacle to NEMA 14-30 and you are done. Metal conduit is a valid grounding path.

This happens a lot, because Goober gets a used 3-prong dryer, doesn't realize you can easily change the cord, and so Goober changed the receptacle from 4-prong to 3. Home Depot still sells the receptacles, which they should not.

SUPERB: Fit a 30A, 2-pole GFCI breaker ($95)

At your service panel, find the 30A breaker powering that outlet. Change it for a 2-pole GFCI breaker. (this requires that GFCI breakers be available for your panel: Eaton, Cutler Hammer, Bryant, Challenger, Square D, Murray, Siemens and GE are available many places. A few others are supported by Eaton CL breakers. For Pushmatic, Zinsco and FPE you're out of luck, but in the last two, your panel is actually dangerous and should go ASAP.)

After upgrading the breaker, change the receptacle to NEMA 14-30 and don't hook up the ground wire.

Finally, stick two stickers next to the receptacle:

GFCI Protected - reset at panel

No Equipment Ground

And you're done. This is safe as houses. It would be almost impossible to kill yourself with your dryer even if you were intentionally trying.

GOOD: Retrofit a ground wire. ($20++++ depending on luck of route)

Run a 10 AWG separate ground wire, bare or green, from the dryer receptacle area (leave 1' extra slack) back to any of the following places:

  • The service panel where the breaker is
  • any junction box with a metal conduit path back to the panel
  • any junction box that has a #10 ground wire going back to the panel
  • Anywhere in the Grounding Electrode System - the bare wires connecting the panel to ground rods/water pipes/etc.

Then, change the receptacle to NEMA 14-30 type and hook up ground. If the old neutral wire is bare, insulate it thoroughly. Shrink tubing is not excessive. It mustn't touch ground.

POOR: Change cord to NEMA 10-30 ($15)

There is a procedure in your instructions to swap the dryer out for a 3-prong cord. It involves changing the cord (obviously) but also involves adding a ground strap tying neutral to ground. This instruction is telling you to "bootleg ground", which is stupid and dangerous, and illegal anywhere but here because of a special exception notched into Code for dryers and ranges. Ugh.

The problem with this procedure is that if the neutral wire breaks, it will electrify the chassis of your dryer. The reasoning behind the exception to the rule is that "Dryers are unplugged rarely, and this isn't likely to happen". This was installed due to pressure from appliance manufacturers, who were scared of losing sales if rewiring was required. The "retrofit ground" option wasn't available then; it's a quite recent development.

LESS POOR, BUT ILLEGAL: Cheat a separate ground. ($20)

Defy its instructions, don't attach the ground-neutral strap, and hang a ground anywhere you can, in some way which is inferior to the Retrofit Ground procedure (which presumably, you are unable to do).

You could do it all neat and proper, like a retrofit ground, but don't. Deliberately make it look horky-dorky. That way nobody mistakes it for a proper, legal retrofit ground.

Of course, this is very naughty.

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  • 1
    WOW, Harp, you are rolling here. But I have a honest question....was the 3rd prong every really a neutral? What's wrong with 2 hots and a ground? I know modern dryers with electronics controlling everything may need a neutral, but they could presumably operate at 240 as well. I mean all our buds across the pond operate at 230-240 with ground and it's OK. Just think you are going overboard here a bit. But if you are as cooped up as I am, going stir crazy in Western Washington state, I forgive you in advance! Take care and stay healthy. Mar 18 '20 at 23:33
  • Our buds across the pong operate at 240V, via a +240V hot and a neutral. Nobody has a +120/-120V setup, because that's not how electricity works. Mar 18 '20 at 23:38
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    @GeorgeAnderson The third prong on a NEMA 10 is always, only, and forever neutral only. Yes, 240V-only dryers are fine. But those go on H-H-G NEMA 6 (Ms. Nope) not H-H-N NEMA 10 (Ms. Ghostface). The difference sounds stupid, but it's so important NEMA actually specced a whole separate series of receps to separate them. Mar 19 '20 at 0:19
  • @user3757614 It came from Edison's DC system, which supplied neutral, +110V and -110V, to run motors @ 220VDC. Edison's slick trick to reduce voltage drop, but center grounding also helped safety. I wouldn't be too boastful about that, though, because that's basically Europe sitting back and taking notes while America bleeds the learning curve. Also you know England does +55/-55VAC (110V center-ground) on construction sites... again for safety. Mar 19 '20 at 0:43
  • @user37576124: Thanks for the correction. That was a dumb assumption on my part regarding 240 in Europe...I Americanized it! Oops! Thanks again. Mar 19 '20 at 14:25
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According to the NEC and NEMA if the junction box that feeds your 3-wire receptacle only has 3 wires and was properly installed while it was still legal to install 3 wire 240v appliance receptacles then it is legal to change the dryer cord to a 3 wire cord if the installation instructions that came with the dryer give instructions to install a 3 wire cord.

Local reg's may place further restrictions.

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  • This is the route that pretty much everyone takes. It's great to talk about adding a ground and upgrading wiring, but the average person isn't going to spend more than the dryer cost to install the dryer.
    – JPhi1618
    Mar 19 '20 at 15:42

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