You can use the weldless fitting from bargain fittings, I used a pair in my 120v kettle, work great, no leaks, easy install. You'll need a step bit to drill holes. You can wire it up with a 240v accessory cable for an AC unit that should be readily available at a hardware store. After that is wired up, you'll have to figure out how to enclose the wiring on the outside of the kettle. I used a piece of plastic conduit and some epoxy, however i've seen various other solutions to this issue involving hardware store parts, if you browse electric build threads there should be some pictures of possibilities.