Converting a 110-volt outlet to a 220-volt outlet requires extensive rewiring and most building codes would require inspection. There is an alternative available: Use a voltage step-up converter. Here's how.
Preparation: A. Remember: Safety is the first priority when working around electrical circuits. B. Determine the electrical load. Rated in terms of power or watts of energy, you need to know what the rating is for the appliance you will be connecting to the outlet. Application is important. Will this new 220-line power a window air conditioner, or an electric range/stove, or clothes dryer, for example? Ask a knowledgeable customer associate at your electrical supply store for assistance or seek advice from a qualified electrician for help. Converters are available for purchase to supply a broad range of power wattage options. Do not use converters when the load requires extremely high wattage (5,000 to 10,000 watts) unless you have a qualified, licensed electrician rewire your outlet. C. Turn off the power to the outlet at the circuit breaker box or fuse box. D. Turn off the main power to the circuit breaker box or fuse box. E. Use a commercial lockout tagging device to warn others not to turn on the circuit while you are working with it. F. Determine the carrying capacity of the cable supplying the voltage to the outlet. You want to find that you have a two-wire cable with a ground wire of sufficient gauge to accept the intended load. The black wire is known as the hot wire, the white wire is the neutral wire, and the other wire is the grounding wire. Using a voltage converter requires that the circuit be grounded, so make sure you have an appropriate cable going to the outlet. The gauge of the wire (established by the American Wire Gauge standard, or AWG) identifies the wire's size and resistance to load over distance. Your household wiring most likely will be 12 or 14 gauge, but do be certain you have a cable with a ground wire. Do not proceed with using a voltage converter if you do not find an appropriate cable such as described. Remove the outlet cover using a screwdriver to back out the holding screw or screws. Look at the wires attached to the outlet. You will find a black wire and a white wire. Make sure you find a green covered or bare wire also attached to the outlet. It generally will be attached under a green-painted screw. Look for the cable rating (AWG) stamped on the outer sheathing of the cable. Use your flashlight if needed and safely pull out the wires for a closer look. This number is often incused into the plastic. Replace the wires carefully back inside the outlet. Replace the outlet cover by reattaching it with the removed screw(s). You now know what gauge wire you have and if it is grounded. The type of cable used must have the appropriate rating to carry the electric load of your appliance once it is converted to 220 volts. Wires do heat up and may present a fire risk if they are not of the correct size. Proceed if the cable is the correct size. Seek the advice of a competent, licensed electrician if it is not. G. Determine the capacity of the circuit breaker or fuse used in the outlet's circuit. Replace the circuit breaker or fuse with the appropriate rated capacity if the appliance you intend to use requires a different current than what is being supplied to the outlet.
Beginning the Installation: A. Read the instruction and operating manuals completely for the converter you purchased and your 220-volt appliance. B. Observe all safety warnings. C. Ensure that your converter will safely power the appliance you intend to use. Do not exceed rated capacities. D. Set the converter to function as a step-up converter. Many units act as either a step-up or step-down converter. You are converting 110 volts to 220 volts. That is a step up in voltage. Models vary when it comes to setting function switches--some automatically apply the appropriate voltage to the outlets on the equipment itself. Read and follow the directions provided with your model.
Installation of the Voltage Step-Up Converter: A. Clear the area around the outlet to provide space for the converter to sit. Many units provide an option to mount the converter to the wall. Do so if you prefer. B. Plug the converter into the wall outlet with the cable attached to the step-up converter. Do not use any type of extension cord. C. Plug your appliance into the converter using the outlet for 220 volts provided on the equipment. Make sure the appliance is set in the off position.
Testing the Circuit: A. Remove the lockout tag on your circuit breaker box or fuse box. B. Turn on the main power switch. Proceed if the circuit breaker does not activate. C. Turn on the power to the outlet. Proceed if the circuit breaker does not activate. D. Visually inspect the outlet, the converter, and the wires attaching the appliance. Proceed if you do not feel heat, see or smell smoke, or hear unusual noises emanating from the outlet, the converter, or the appliance. E. Adjust the settings of your appliance according to the manufacturer's instructions. F. Turn on the appliance.
Troubleshooting: A. Turn off the equipment if the appliance does not function properly on all settings, or if the circuit breaker or fuse is activated after a period of time under load (running the appliance). B. Check your cable rating, circuit breaker or fuse capacity, requirements of your appliance, and the converter instructions to ensure you have faithfully followed the manufacturer's instructions. C. Seek competent advice from a licensed electrician if you cannot determine the cause. Do not use the outlet or appliance until you know it is safe to do so.