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.

Peter