180 degree out-of-phase" voltage level.

Are you certain you don't mean 120- or 240-degrees out of phase?

How does one get two lines 180-degrees out of phase?

240V single phase, commonly supplied to single family dwellings, has a
center tap and two hot leads which are 180 degrees out of phase to
supply
higher powered items such as air conditioning and electric stoves. In
addition, approximately half of the lower powered items, such as lights
and
the refrigerator, are powered by each of the two legs to the center
tap--which is approximately ground potential.

Ahhh! But where does the 240 come from?
Does it not come from two of the three legs of a Y or Delta?
These are square root and cube root functions.
If they were 180 out of phase, it would cancel.

They add, rather than cancel, and do come from two legs of a delta.

Remember that the power is transmitted down the street at a much higher
voltage, and the drop to each small cluster of residences is the output of a
transformer with its center-tap referenced to ground potential. The ground
wire, in my part of the country, also serves as the messenger cable
(physical structure) and is the bare wire that you see when you look up at a
typical residential service drop.

Peter