"Joerg" wrote in message
et...



In the US it is not very common to have three-phase available at the end
user. Part of our community does have a three-phase distribution at the
kilovolt level. Then they hang each transformer between two of the
phases. Pretty much in a statistical or round-robin scheme to provide a
somewhat equal load. The transformer secondary is a center tapped
120V+120V and typically feeds 3-5 houses.

Industry sometimes uses three-phase but I remember a case where a
business wanted to get that and the CEO almost fell off his chair when
he received the quote from the utility. Then they opted to buy the
diesel generators they had rented as a temporary power source. This is
what you get with monopoly situations I guess.


I did the network and phone wiring at a metal fabrication shop last year.
The 17 automated welders required such an amount of power that the
utility had to replan the area due to draw these machines demanded.

The company did specialized fabrication for semiconductor fabs and
other clean rooms.

I think it's impressive when you can suck down the grid!

The scary part is to see the differences between the plan and the
'as built' considering some of the chemicals inside the pipes.