I have a Kitchenaid Artisan 5qt stand mixer that sparks and kicks the breaker when switched on. I removed the ground. Now, it comes on when plugged in, even when the switch is in the off position.

I agree in a wiring situation a KitchenAid Service center is the best place to go to, here is a link to KitchenAid's service center locator: SERVICE LOCATOR However a lot of areas do not have service centers and if you call KitchenAid 90% of the time they will send you to us (The Mending Shed) as we are one of the only service centers that not only works on these mixers every day but we will actually take the time to help you diagnose the mixer and repair it correctly.

It does sound like you have a short to ground. The answer is definitely not taking the ground wire off, so put that back into place. Remove your end cover and look at the speed control plate make sure you do not have any loose wires. If you do not see anything then most likely one of the wires that come off of your field and connect to the brush holder has come loose and is shorting out. The kitchenAid service manual has a full wiring diagram and instructions on how to check the wiring in the mixer. Here is a link to the service manual: http://ep.yimg.com/ty/cdn/mendingshed/kitchenaidservicemanual.pdf The last page of the service center is where you will find the wiring diagram.

Once you have corrected the wiring check you speed control lever and link (also found in the service manual about page 7) and make sure that the speed control link is positioned correctly so that the mixer will shut off when set to the off position.

If you need any help please feel free to call or chat with us and we will help you the best we can so you can get your KitchenAid mixer back up and running.

- Colleen @ The Mending Shed

Please unplug it and leave it alone. The earth wire is a life saving device put there to stop you killing yourself if something goes wrong. It is not a little green wire that you can remove on a whim even if just for testing purposes. Your mixer is unsafe if plugged in without it.
The fault is unlikely to be a big deal as far as expense goes, a proper service agent will be able to locate the fault using their eyes and a multi meter. I would be looking for broken or partly detached wiring inside, maybe even insulation worn through somewhere.
Phone Kitchen Aid and ask who your local service agent is.