I had a family member in an apprenticeship program tell me over the holidays that one of his teachers who is involved in the power distribution industry told them they are now experimenting with DC distribution on ultra high voltage distribution lines to minimize impedance losses. Third hand info, so don't beat up too much on details-but if that is true, sounds like things are still evolving and we may have come full circle.
There has been a megavolt (+/- 500kV pole-ground) DC transmission line between The Dalles, Oregon and Sylmar, California since about 1970. http://en.wikipedia.org/wiki/Pacific_DC_Intertie
As for industry confusion, I installed a new dryer Monday. Their instructions said to connect the "neutral ground". What does that mean?!
I don't know what that means either,
because it's an invalid term
but I hope Mike will enlighten us.
Ideally, you will use a 4-wire cordset on the dryer with a NEMA 14-30 plug, connecting into a NEMA 14-30 receptacle. On the terminal block of the dryer there will be a jumper to connect between the neutral terminal and the chassis of the dryer. Remove this jumper.
If, on the other hand, you have a 3-wire NEMA 10-30 receptacle, check to see if there are separate ground and neutral conductors in the receptacle box. If so, replace the 10-30 with a 14-30.
If replacing the receptacle is not an option, then you'll have to use a 3-wire cordset with a 10-30 plug. In that case, you will connect the jumper between chassis and neutral. This, along with kitchen ranges, is the ONLY acceptable bootleg ground anymore, and then ONLY if the receptacle cannot easily be replaced with a NEMA 14-30.
This diagram is not comprehensive.