A quick and dirty test comes to mind.
Anybody got two of the immersion water heaters used by travelers? http://www.amazon.com/Bush-CH-101-Energy-Saving-Immersion-Heater/dp/B003DLB5 KW The idea would be to place two of them in a semi-conductive liquid (water with a dash of salt), and apply higher voltage to one of the two, to see if there is current between the two . .not sure if this is as simple as it sounds.
