On Thu, 30 May 2013 17:07:31 -0400, Edward Reid
wrote:

On Fri, 24 May 2013 09:47:25 -0700 (PDT), harry
wrote:

Putting loads like this on a single phase system causes voltages to
appear on the neutral which can upset RCD devices.

If a 240V device is connected to a neutral, then there's an
electrician whose license needs to be revoked. Retroactively.

Are ovens and clothes dryers 240V? Every modern installation has a
neutral.

What's usually called single phase is really two-phase -- two phases
180 degrees apart.

Wrong. It's really a single split phase.

Three-phase has the phases 120 degrees apart. Two
phase is fine for balancing. You really only need three-phase for
certain kinds of electric motors, which for obvious reasons aren't put
in appliances destined for residential use.

Completely wrong. Three phase isn't put in appliances for residential
use because three phase isn't installed in residences in the US. In
many places it's not even available at the street in residential
neighborhoods.

With either 2-phase or 3-phase, appliances which need 120V are
attached to one phase and a neutral. With 2-phase, appliances which
need 240V are attached to both phases. With 3-phase, appliances which
need 208V are attached to any two phases (dig out your trigonometry to
figure out where the 208V comes from). Three-phase motors are more
complicated ...

Wrong. Don't give up your day job.