Davy wrote:
What would be the result if an electric hot water heater wires were
reversed?
If the wires going into the hot water heater were red wire to black,
black wire to red, what would be the result when the hot water heater
was started up?

Your water will be the wrong polarity. When you open both the hot and cold
faucets, it will not mix properly. Sort of line trying to get two magnets
to stick together when the N & S are reversed. In the washing machine, the
agitator may overcome it, but showers will be most uncomfortable.

--
Ed
http://pages.cthome.net/edhome/