What is a Phase:

	Understanding phase terminology is important to anyone working
with electricity. The windings of a transformer can be wound and or 
connected in many ways, single phase (the normal connection for a home),
three phase (the normal connection for industry), or two phase used
in many areas of the world. 
	In electricity, a single alternating current is termed single
phase current, there will be two 120 volt hot wires and one grounded 
wire (not the ground) the neutral. In three phase there will be three
phase wires carrying three currents differing in phase by 120 degrees,
and one neutral or grounded conductor. In a diphase system two currents
flow, differing in phase by 90 degrees. 
	One transformer may contain these windings or two transformers
may be connected together to arrive at the desired voltage and phase. 
	As mentioned, In a single phase connection there will be two 
hot wires each of these wires will have a voltage of about 120 volts, 
and 240 volts from hot to hot. In some three phase connections, the
three phases may all be 120 volts, this is 120/208 volt connection,
meaning, that each hot wire to neutral or ground is 120 volts, and the
voltage between any two of the hot wires will be 208 volts. In some 
three phase transformers provide two 120 volt wires and one wire that
has a much higher voltage,(approximately 190 volts), called the wild leg.
You do not want to connect a 120 volt circuit to this leg, but the 
voltage between this leg and either of the other two hot wires will be
about 240 volts.
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