Be careful when removing the old hood. That same wire that is feeding the hood will be used to power an outlet for the new microwave oven. Do not cut the wire. The new microwave must be a minimum distance from the top of the stove. Before purchasing the microwave oven, look up the installation manual online to get the installation details.
It may not always be possible to use the old hood electrical feed to power the new microwave oven. It might not be a 20 amp appliance circuit. The wire may be too short.
Click here to see more photos of an outlet box being installed using Madison Bars.