[jebennit]

I bought a new dryer that came with a 3 prong cord so can't I just take the cord off my other dryer and hook up the same way Black / Nutrual/Green from in dryer Red /
Green to ground spot on dryer Hope you can understand that just the same as it came off other dryer??

[ohb0b]

First, an explanation about dryers and house current in general.

You receive power from the utility at 120/240 volts. There are four wires in you circuit breaker panel:

Black, Red, White, Green (or Bare)

If you measure voltage between the wires you will have:

Red-Black = 240 volts
Black-White = 120 volts
Red- White = 120 volts
Black-green = 120 volts
Red Green (bare) = 120 volts
White-Green(bare) = 0 volts.

Since the dryer needs 240 volts for the heating element and 120 volts for the motor, you need the black, red, and white wires at the receptacle.

Here's where it gets confusing. At the main breaker panel, the white wire and the green wire is connected together, then connected to a grounding electrode, which can be a rod, a buried plate, or a cold water pipe. The white wire is technically called the groundeD conductor, and the green wire is called the groundinG conductor. (Emphasis is mine)


People usually refer to the white wire as the Neutral and the green or bare wire as the ground. The white wire is used to complete the circuit on a 120 volt line. The green conductor is for safety, it connects all the non-current carrying metal parts of the circuit to the ground. The green wire normally does not carry current. It is there to make a short circuit and trip the breaker in case a hot wire comes in contact with a metal case. (The grounding system also helps protect against surges, lightening strikes, and other dangers, but that's a whole semester of electrical theory.)

Getting back to the dryer outlet, the only place the green and white wires should be connected together is at the main service box. In the past, we were allowed to use the white conductor of a cook stove or dryer as both grounding and grounded conductor. I have heard the theory that this was first allowed in the 1940's as part of a campaign to save copper for the war effort. It's as good a story as any.

Connecting the neutral and ground together at the dryer created a potential safety hazard, and in the last code cycle, they finally eliminated the practice, hence the difference in your dryer plugs.

Since many homes are still wired with the 3-prong method, the dryer manufacturer installed a 3-prong plug.

If the dryer was supplied with a 3-prong plug, there is a bonding strip that connecets the metal case of the dryer to the white wire.

To use a four prong plug, you must also remove this jumper.