I have a 40 gal glass terrarium with one 18" ball.

First off, I have a TropicAire humidifier/air exchanger, and the instructions say to completely cover the screen terrarium lid. I covered all but 9x2 space because I didn't quite trust it. The temperatures and humidity seem to be holding well so far, but is it safe to have so much of the lid covered, even if the humidifier is an air exchanger? I also have a Zoo Med ReptiTemp 500R thermostat probe running into the tank through a small hole in the open space. The ball likes to sometimes wrap himself around the probe cord (it's secured though) and either just hang there or nose around the uncovered screen.

Which goes to my second question. Is there a danger of electrocution with him wrapping around the thermostat probe cord? The water dish isn't near it, but he could drag himself through the water and then up the cord. Should I somehow secure it so he can't wrap around it?

Thanks in advance.