Why Do 240V Circuits Not Require Neutral?
In a 120/240V single split phase system, the two ungrounded (hot) legs are actually connected to the secondary winding of the distribution transformer. The transformer actually steps down the voltage to 240 volts, so the two legs are a complete 240 volt circuit.

The grounded (neutral) conductor is connected to the center of the coil (center tap), which is why it provides half the voltage.



Therefore, if a device requires only 240V, only two ungrounded (hot) conductors are required to supply the device.  If a device runs on 120V, one ungrounded (hot) conductor and one grounded (neutral) conductor are needed. If a device needs both 120V and 240V, then two ungrounded (hot) conductors and one grounded (neutral) conductor must be used.

If you connect a load between the two ungrounded legs of the circuit, you can see how you have a complete circuit through the coil.



If you connect a load between one of the ungrounded conductors, and the grounded (neutral) conductor. You can also get a complete circuit, though it's only through half of the coil.




Since these circuits only include half the coil, the voltage is also half (Es = EpNs/Np).