On Fri, 3 Aug 2018 07:42:56 -0700 (PDT), trader_4
wrote:

On Friday, August 3, 2018 at 12:02:12 AM UTC-4, wrote:
On Tue, 24 Jul 2018 08:57:29 -0700 (PDT), trader_4
wrote:

On Tuesday, July 24, 2018 at 11:28:39 AM UTC-4, Bubba wrote:
On 7/24/2018 9:53 AM, trader_4 wrote:
Take two generators built on a single shaft (the same way that three-phase generators are built on a single shaft) so that you get two 120VAC outputs that are 180 degrees out of phase. Would it be reasonable to call this two-phase power?

Bubba, what's your answer?

The transformer for my house has a single phase input.Â* The output of the transformer is single phase as well.Â* I don't have a two-phase generator on my utility pole.

There you have it, typical. Instead of responding to the simple questions
that go to the heart of the matter, just diversion. Others can note that
I responded to your oscilloscope connection question. Note that I also
gave you an opportunity to define for us what makes a system one phase,
two phase, N phase and then explain why residential doesn't meet the
definition of two phase. If you can't define it, then it becomes
arbitrary. Which is kind of what I and the moderator at the forum said,
it's just semantics.


OK lets try this one more time. At my utility I decided to ground one
end of the secondary (L1) instead of the center tap. (like most of the
civilized world according to Bod) I still center tap the transformer
and have 3 buses in my service panel. (lets ignore how you would need
to do overcurrent for now but the answer is a split bus panel).

Everything works exactly the same except I have the neutral
(centertap) bus at 120 above ground and L2 is 240v above ground.
Nothing in your house will notice the difference if you are not using
the EGC (ground) for a current carrying conductor (a violation of
250.6)

Do you still think I have 2 phases?

http://gfretwell.com/electrical/End%...nter%20tap.jpg


Yes, because your neutral is still connected to the center tap.
So, inside the house you will still see two hots at 120V with respect to
the neutral, one 180 deg out of phase with the other, or of alternate
polarity if you like. Hook up a scope, connecting the scope ground
reference to the neutral. The SYSTEM neutral, not some parlor trick
point that I've been accused of using. What do you see? Two hots,
120v, 180 out of phase.

But you can't even do your parlor trick now because the ground on the
scope would be connected to 120v and kaboom.
Who cares what the signal looks like there anyway?
This is quite clearly a single phase source that is 120 and 240 above
ground yet it is wired exactly the same way.
The only thing I did was move where I land the MBJ. It is just easier
to see that in any given instant current is flowing anywhere in the
circuit in exactly the same direction.
If I don't use the center tap to supply 120v loads towards L2
it is actually not a bad way to do things because it would allow
single pole breakers everywhere, That will be important when they
expand GFCI/AFCI to the 240v circuits, I could draw how you would hook
up an existing panel that way if you haven't figured it out by now.
At the end of the day, landing the neutral on the center tap was just
an arbitrary decision by Westinghouse to allay some of the fears of
his "killer" AC.