Blood also conducts electricity, maybe that's what uniting two otherwise unconnected puddles of water. Electrical spell also have spread area around where they hit, maybe it's large enough to hit both puddles and electrifying everything. This is why I generally disregard air spells besides the utility ones, the shocked/stunned area tends to be too unpredictable.
Can someone give me some combat tips concerning the elements and their connectivity such as rain + air skills. It seems to be unpredictable and it backfires for me constantly, stunning and damaging my melee chars. Which area/puddles of water getting electrified seems a bit random in how the effect is spread. Sometimes it's spreading quite far other times not so much or not at all, even if there's a lot of water.
You can get rid of water before using any electrical spells. If you transform water into ice or override it with poison or oil it won't conduct electricity.