Wood,

Yes, the electricity will travel through the water, if given the opportunity (a path). But your little yellow plastic insulators will keep that from hhappening. I have ponds with the rebar rods actually stuck into the water. No problems because the insulators keep the wire from touching the rebar or the water.

By the way, one wire is as effective as three. Just put it high enough that the horses can't step over or duck under without touching and one wire is enough.

Nick Smith