> (i.e. also back through the ground wire) are unequal. You mean neutral or return wire. No current should be normally passing through the ground wire. In fact

> (i.e. also back through the ground wire) are unequal. You mean neutral or return wire. No current should be normally passing through the ground wire. In fact in the US at least, GFCIs can be used on grandfathered ungrounded outlets. When you buy GFCI outlets they come with little stickers: “No Equipment Ground” to affix on the outlet in that case.