You need 12/2 romex, 20 amp breaker, proper tools, proper fittings on as needed basis. Then begin to plan your route with romex from dishwasher to electrical breaker panel. The best way to run this wire is through floor but sometimes that is not possible. Routing through wall space, running up or down between wall studs is the most difficult. Sometimes you will have to penetrate the floor or ceiling base plates. This is the top and bottom corners of the wall, it is doubled up 2×4 wood studs. These wall plates usually have to be drilled at 45deg angle with a high amp slow turning drill and 8-12inch wood bit. Some of the very old homes(100yrs and older) have oak and 24 inch footers that block your route under the corners of the house. I can’t go into a large amount of routing in these old homes because of so many variances. If you get your wire run and still need help with that or the wire connections, then would be good time to ask any questions. Most of the time pulling the wire is technically easy just a lot of hard work. Try to get that done before asking any questions because its not much to talk about unless you are undecided where to drill. You can ask and we will try to help with that too. The most difficult way to route will be from the top in attic then down the wall to GD. I would come up from the crawl space if possible.
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