>I think it would be unsafe to not have a neutral on power poles, relying on ground, as this would put a high potential into ground Three-phase transmission lines usually do not include a 'neutral.' I don't care what you think. >With a multi-phase system, if you have equal loads one each phase there will be little current on the neutral line, so you can have a thinner neutral conductor. Loads on each phase are rarely equal. Three phase power systems with delta-connected transformers can handle unbalanced loads. There are three conductors with no 'neutral.' The thinner gauge conductors that you observe on transmission lines are not intended to carry current but instead are ground wires for lightning protection. If you were to use wye-connected transformers a fourth conductor would be required as a neutral, but this is not considered cost-effective. >I think you could still do GFCI with this, by having those detectors provide a small path from ground to the (floating) hot, to monitor current flow through. Again, I don't really care what you think.