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When connecting a 3-prong cord to a new dryer is the middle wire on the cord the ground and does it make a difference where the other 2 wires go?

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2015-07-17 17:35:21
2015-07-17 17:35:21

For USA, Canada and countries running a 60 Hz supply service.

The short answer is yes, the center terminal is the ground wire, and the order of the two hot wires (red and black) does not matter, so long as you don't attach them to the same lug.

If you have a four wire plug in the wall, and are converting a 3 wire appliance, YOU NEED TO USE A FOUR WIRE CORD AND NEVER, EVER CONNECT THE GREEN AND WHITE TOGETHER ON THE CENTER LUG.

If your appliance is old enough, it will have only 3 connection terminals and no place for the ground wire to go. I repeat, DO NOT EVER just put the green ground wire on the center screw terminal, ESPECIALLY if you have a four wire outlet in the wall of your new home. If you do that you will just only be cheating yourself , your wife and anyone else in your house out of a great new safety feature.

What you need to do for an old appliance that has no place for a ground wire is this: you NEED to drill a small hole through the metal case on the dryer that will take a small nut and bolt, and you also need to sand off all of the paint around this nut and bolt so that it will get good contact with the metal case.

So, after you are done, stick the bolt through the hole, install a locknut and tighten it down as much as you possibly can.

Then, you can put the ground wire on the bolt, and install another locknut on top of the ground wire, and also tighten it down as much as you can.

This is the only proper way to upgrade an old appliance to 4 wire.

Also, on an old appliance, there should be a strap connecting the center terminal where the white neutral goes on your older appliance: this strap connects the neutral to the case of the appliance. YOU MUST remove it or cut it by any means necessary or you will just be stuck with a 4 wire upgraded appliance that still acts like a 3 wire. Never just connect the two green and white together if you have 4 wire.

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for USA, Canada and countries running a 60 Hz supply service

Short answer: yes and no. Some homes built during a certain period can.

Before a new code is adopted there is a lot of anticipation about newer code requirements, and new code requirements usually send manufacturers of products scrambling a year or two before to come up with products that meet the new requirements. But the government almost always allows them to sell off their old stock for a period.

If your home was built very late in 1994, to 1996, when the latest code was adopted, you may already have a 4 wire cable installed with a 3 prong outlet: the installers would just connect the ground to the outlet box or not at all and be done with it. So, in some limited cases, you just might be able to upgrade an outlet from 3 to 4 prong, and still be safe about it.

Otherwise, if the cable only has 3 wires in it, NO, NO, NO.

One exception to that rule: if you have got one of the one in a zillion homes where the builder cared enough to wire it with EMT (conduit). Then, to change anything at al is simple to do: you just run the fourth wire through it. Simple as that.

The reference to Neutral being ground is entirely INCORRECT. Neutral is NOT GROUND.

Wiring a home with EMT is NEVER done. I have been doing this kind of work for a very long time and have never seen or used EMT in a residential application. IN garages, yes, IN industrial environment- It is required but never in a residential situation.

The simplest answer to the original question is: If you presently have a three wire outlet, there would be no need to change to a 4 prong outlet unless some local requirement makes it necessary. The feed to the new outlet would have to be upgraded to a three conductor plus ground .

Other answers

It can BUT there is a reason why you shouldn't do this unless you are a Licensed Electrician: if the appliance NEEDS a four prong receptacle and you just change the receptacle without wiring it up correctly, it will probably be UNSAFE and will also void a) your home's fire insurance cover and b) the warranty of the appliance.

In my 30+ years of experience, a lot of people want to save money on the most dangerous energy source in their home.

It makes much more sense to call a Licensed Electrician and pay to have it done right.

<><><>

(LIFE SAFETY WARNING! [Disclaimer]

Electricity is dangerous!

You can be injured or killed!

Improper installations can cause fire, injury and death!

Should you be doing this yourself?)

1] No!

2] I take it you have a new stove or dryer

3] The old outlet is three prong

4] The new appliance is 4 prong.

5] You have 2 choices

6] Install a new supply cable to feed the appliance with a 4 prong outlet OR utilize the exception to grounding which is allowed in the NEC for existing circuits which lets you reconnect the chassis ground to the neutral [ground] third conductor and change the cord set to a three prong cord - check to make sure your township has not superceded these allowances - the "authority having jurisdiction" has the last say.

7] Secure appropriate permits.

8] Install the equipment according to standard practice in a workmanlike manner!

9] Secure underwriter's inspection! [For your peace of mind.]

or ... call a licensed electrician.

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This will vary by state. Turn off the power remove the old device. If there are 4 wires present then the device can be changed. If not your local inspector may be able to offer some alternatives.

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You may need to run new wire to your outlet. Older 3 wire plugs had two hots and a neutral, no dedicated ground. So there may not be a ground wire, or there may not be a neutral wire in the box. You need all four wires to safely wire that new outlet. The new outlet is safer (which is why they changed), so take the time to install it correctly.

<><><>

As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.

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Back to the original question, which was a new dryer being installed in a house with a three-prong dryer outlet.

Your three-prong cord has two thick wires and a thin one. The thin one, which is in the middle, is neutral not ground. When you remove the cover plate over the electrical connections on the new dryer you'll find a terminal block with three screws, and a green screw for ground a couple inches away. Leave the green screw alone; do not connect anything to it because this cord has no ground. The middle wire goes to the middle screw on the terminal block. The two thick wires go to the other two screws, and it doesn't matter which thick wire goes on which screw so long as you don't hook them to the same screw. (Yes, I've seen it. No, it didn't work.)

Now! If you call an electrician and get this outlet changed to four-wire service (which will either be Not Cheap if the electrician can find a ground in your laundry room or Extremely Expensive if he's got to pull wire), the new cord will have red, black, green and white wires coming out of it. Green is Ground, and goes to that green screw you ignored with your three-wire cord. White is neutral (middle screw) and the red and black wires, which are hot, go to the two outside screws.

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2015-02-03 05:12:27
2015-02-03 05:12:27

Dryer receptacle three to four
You are approaching the problem the wrong way around. The cord to the dryer should stay a four wire as that is now the new electrical code. What should be done is changing the three wire wall receptacle to a four wire installation.
Turn the breaker off that controls the circuit for the dryer. Look in the back of the dryer receptacle box that is in the wall. The three wires coming in should have a bare ground wire in the cable set. It wasn't brought to the receptacle because there was no place for it on the old three wire receptacle. If you find the ground wire back there under a screw terminal, just add another short piece of wire under the screw and then connect the other end of the short wire to the new ground terminal on the new four position receptacle. The wire should be equal in size to the size of the wire that exists around the ground terminal now. If the house is so old that the range cable did not have a ground wire in it, the electrical code allows a separate green ground #10 wire to be taken from the breaker panel box to the existing range receptacle. This wire is to be bonded on each end. At the panel end to the ground bus and at the receptacle end around the ground screw at the back of the box unbroken and then to the new four position receptacle ground lug. The two outside terminals of the new receptacle can be interchangeable. Red wire left or right, black wire left or right.

As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.

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0

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