I just moved and the house is set up for a gas dryer, I have an electric dryer. Can I convert my existing 120 outlet to support a 240 outlet, or do I need to run new wire.

You need a new wire, breaker and receptacle.

A "standard" 120v receptacle is completely different from a 30A-120/240v 4-wire dryer receptacle.

Absolutely not!

A new four wire circuit must be run. You need to know the amperage required by the dryer to properly size the circuit. Also, a 20 amp 120 VAC is required to be installed in the laundry room.

If the dryer requires 30 Amps, then a 10/3 AWG cable must be used. Also, you will need a DPDT 30 Amp breaker to be installed in the Main Service Panel. <corrected amperage ratings and cable size. Brain dead monment!!>

The receptacle should be a 50 Amp receptacle for a four prong plug.

Black will go to one load position. Red will go to the second load position. White goes to the Neutral pin and Green green goes to the Ground pin.

If you do not know how to work on a Main Service Panel, then I strongly suggest that you contact several licensed electricians to plan and run your needed circuits.

Don, just a question. When have you seen a dryer that required a 40A circuit?
Aside from commercial and funky European models, 99.9% of the ones I have seen were 30A.

Stan,

Just an answer, never! Thank you. I will edit the item.

I was using the 40 amp rating as an illustration because for the life of me, I did not rember the 30 Amp rating.

I even checked the 2008 NEC and could not find it. Call it a very senior moment.

Hey, no problem. I was really just wondering.