I'm afraid that I have a cat that likes to spray it's territory and sometimes it does it on the electrical outlets. Of course, then you see sparks from the wire getting wet. Is there anything I can do to stop the sparks without having to turn the power off (one outlet switch also goes to the fridge so I cannot turn the powerbox switch off for too long).

What do you do when your outlet gets wet and sparks? I cannot turn off the power switch to one for too long as it also connects to the fridge.

First off... fix the cat. He will always spray in that same area regardless of how many times you try to clean it. Regarding your outlet, for it to spark it must find a ground and cat pee sprayed on an outlet should not, in and of itself, make this occur. My guess is, by way of your fridge also being on this circuit, your outlet and accompanying wiring is probably quite old. I would suggest replacing the outlet first, this is very simple but I would recommend turning the power off first. I could be wrong but I doubt that it is a wiring problem, the sparks that you see is a clear indication where the problem exists.

I suggest you try one of those products that "keep electriity from leaking out of the outlet", just kidding, but anyway, something from these child safety outlet covers from below might help.

Find Safety Outlet Protectors and other Childproofing at Aubuchon Hardware

Replacing the outlets to get rid of all the corrosion might help in the long run.

And for a little added piece of mind, add a power failure alarm:

THP207 - POWER FAILURE ALARM & SAFETY LIGHT - Home Security Store

The cat might get the hint.