Replaceing 4 prong outlet my dryer is 3 prong i bought 3 prong outlet there are 4 wires comeing out of wall white black red n a bareground wire there is only 3 post to connect which wire besides the white do i or better which 1 is not connected

This should help.

https://youtu.be/UepkgOmobPE

It's either you convert the 3-prong outlet to 4-prong or the 4-prong cord to 3-prong. But the latter is easier and more feasible. Unplug the dryer then disconnect the 4-prong cord from the dryer. Note that it has red, black, white, and green/yellow wires but sometimes the red and black wires are both replaced by same color wire, usually gray. The red and black wires are lines L1 and L2 reversibly, meaning they can switch places, while the white and green/yellow wires are the neutral line and ground, respectively.

Get yourself a 3-prong cord and note that it has red , black, and white wires but sometimes, like the 4-pronged one, the red and black wires are both replaced by same color wire, usually gray and can also switch places. All you have to do now is connect these 3 wires in the same manner they are connected as 4-prong cord to the terminal block. The wire strapped to the dryer cabinet and connected to the green/yellow wire of the 4-prong cord wire is now left hanging. The last step is to connect this hanging strap wire to the same terminal on the terminal block (center) where the white wire (neutral) is connected and it's done.

It can be observed that converting a 4-prong cord to 3-prong cord is merely joining the neutral line (white) and the ground (green/yellow) thereby reducing the number of prongs from 4 to 3. On the other hand, converting a 3-prong cord to 4-prong cord is merely splitting the neutral line and the ground thereby increasing the number of prongs from 3 to 4. The link below might enlighten you further on this matter.

Electric Dryer Prong Conversion

Hi jjjjme...
Go to the following webpage and see a explaination and picture of how to wire your dryer.
Please take time to rate me

http://www.selfhelpandmore.com/switch-outlet/dryer-circuit-wiring-and-hookup.php

Hi tclark6054...

Go to this webpage and see a picture of how to wire your dryer, this should solve your problem...
Please take time to rate me

http://www.selfhelpandmore.com/switch-outlet/dryer-circuit-wiring-and-hookup.php

The 4-prong plug has red, black, white, and green/yellow wires while the 3-prong plug has red, black, and white wires. The only difference is the green/yellow (ground) wire of the 4-prong plug which is attached to the dryer cabinet. All you have to do is connect the wires of the 3-prong plug in the same way the same wire colors are connected with the 4-prong plug then connect the terminal on the cabinet, where the green/yellow (ground) wire of the 4-prong plug is formerly connected, to the white wire of the 3-prong plug.

Your four prong cord has 4 wires. Black,Red,Green and White.
Remove the 3 prong cord from the dryer.
The Black and Red wires go to the outside terminals on the dryer. The White wire goes top the center terminal. The Green wire goes outside the terminal cover to any nearby screw for grounding.

The laws in most states are changing to where the NEC Code requires the use of this 4 prong plug. It is quite common to see this 4 prong plug installed in new apartment buildings and rental properties because of this law requirement.
So what you have is a red, black, white and green wire on the dryer side of this wire plug.
The red and the black wires are your hots (110 volts) and shall be connected on each outside screw of the drier electrical terminal and the white wire (neutral) shall be connected to the center screw.
So now you are left with an extra green wire with no place to hook it huh?
I suggest just loosing one of the drier electrical terminal mounting screws and hooking it there. The ideal here is to ground the outside body of this machine to prevent possibility of electrical shock if water is present (like a leak somewhere nearby).
In actuality this really serves no viable purpose because the white wire does exacly the same thing, just in a different manor,,, but hey,,, our law makers are not certified electricians either. They just like new ways of stimulating sales and profits.
.
Note: if you are in a rental property and this 4 prong wall receptical is installed, I would not suggest you remove it or change it in any manor, as this will open yourself up to possibile legal liabilities if an incident were to occur,, like fire.

YOUR FOUR WIRE CORD IS AS FOLLOWS RED,BLACK WHITE AND GREEN ON YOUR DRYER YOU HAVE FROM LEFT TO RIGHT 123 CONNECTIONS THE TWO OUTERMOST(1 AND 3) ARE HOT LEADS SO HOOK RED TO 1 AND BLACK TO 3 NOW HOOK WHITE TO 2 AND THE GREEN CAN BE ON THE TERMINAL COVER SCREW OR NOT AT ALL BUT BE SURE IT CANNOT COME INTO CONTACT WITH RED OR BLACK

If you had a 3 prong originaly you probably have only 3 wires to work with, either a red and black and white or a black and a black with a red stripe and a bare stranded wire. The black and red are ALWAYS the 2 hot wires 230 volt. The white or bare are the neutral / common wires. If you only have 3 you will need to get your equipment ground from a cold water line to the 4th prong.
Another option leave the 3 prong in the wall and install the old 3 prong pig tail on the new dryer then ground the frame of the dryer to the nearest cold water line. The water line must be metalic for this to work.
Dave

This is common issue. Due to some building codes the 3-prong configuration is no longer used in homes. The wiring is similiar with one exception. The 4-wire plug uses an additonal (WHITE) NEUTRAL wire.

Here's a brief explanation of how the plugs are configured:

Dryer 3 prong wire configuration:

RED - 120 VAC
GREEN - GROUND
BLACK - 120 VAC

Dryer 4 prong wire configuration:

RED - 120 VAC
GREEN - GROUND
BLACK - 120 VAC
WHITE - NEUTRAL

BOTH plugs provide the SAME source voltages to your appliance:

220 VAC - provided across the RED and BLACK leads are what drives your heating circuitry.
120 VAC - usually tapped of the BLACK wire is used to run the drive motor and timer on MOST dryers.

The wire terminal block in the back of the dryer should have a black, white, and red wire running to it from the dryer wiring harness. With the 4 prong plug, simply attach the BLACK, WHITE and RED wires at the terminal block ensuring that you match the RED and BLACK wires as they are configured and attach the WHITE wire at the remaining terminal lug. Make sure you screw them all down securely. Attach the remaining GREEN wire to chassis (dryer frame) ground. I hope ths helps you.