I cannot see any problems with what you want to do.

I would put the electrical box off to one side in the cellar.
Then loop your electrical cord down and then up to the box.
My idea here would be that if the dishwasher leaks water will run into the hole in the floor and then drip off the bottom of the loop instead of dripping into your electrical box.

One other thing that I do with dishwashers is to put a drip pan under them.
They do make pans for this but they are hard to find and relatively expensive so I just get one of those plastic trays that they use to put wet boots on. They have about a half inch lip around the edge. Although they do not protect everything under the dishwasher they can be positioned to protect most of it. At home my dishwasher is over the utility room so I put a drain line in. Since we are in that room often doing laundry we will see a leak.
At other locations I have just cut out a part (an inch or so) of the lip at the front so that if there is a leak, water will run out under the kick plate onto the floor instead of rotting out the floor under the unit because I did not know there was a leak.

The water valve is often outside the tray so I make a small tray out of tin foil so it is also protected and will show me if a leak develops.

Hello again denman, ... well I did the box wiring, ... hooked up the water line, there's a small leak (I know, there is no such thing)from the Cu fitting of the cellar supply line. I'm going to solder a male adapter to that feed in.
Ran it through a high temp wash cycle, ... have a leak under the unit. Appears to be a solenoid activated piston shut off that isn't functioning properly. I've an idea the solenoid is on it's way out as I'm hearing a bit of a grinding sound (as in a disposal) that comes and goes, but last for only one to two seconds. The piston seems to malfunction during a change of cycle, then there is leakage of water until it closes. Maybe a matter of an "O" ring within the mechanism? Gave it a shot of WD-40, ... really didn't improve. So with this information, ... can you offer an thought or two? The piston may be bad, ... or the solenoid, ... or both. Is this an easy swop out on this machine, if it is in fact a solenoid problem? It's a Hotpoint: model # HDA3220Z04BB

Hello there denman, ... you are truly a blessing. I put some dishes in this washer tonight, running them through now, ... and I checked again as to the leak and it's origin. It's certainly coming from the shaft, and the solenoid is functioning (wrap on wood) as it should. This machine I was told "wasn't used much", ... might be the reason the seal isn't sealing. I had an auto mechanic that once told me car was fine. He said "the spark-plugs spark, the carburetor carbs, ... and the pistons do what they're suppose to do". I haven't a quick thought on what the functions of this dish washer does, ... and how it does it, ... maybe you'll have a few thoughts as my auto mechanic. Not many things rhyme with 'shaft'.
Just want to say "Thank you" for all your help and information. I'll be ordering the "Push on Nut" and "Shaft Seal" in a matter of minutes from "Appliance Parts Pro". Thanks for all you do on this page. There's a place in heaven for you!

Best,
Polly147