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RE: No difference only the voltage and frequency have changed

Posted by coffee-phil on September 9, 2011 at 15:47:55:
I can only speek with any sort of authority about US power. I assume it is similar in New Zealand. In the US most residences get 120 Volts for lighting and most appliances, and 240 Volts for large loads such as clothes dryers, ovens, and air conditioning compressors.
The house is fed from the secondary winding of a transformer. This winding is center tapped with 240 volts from end to end. From either end to the center is 120 volts. The center is connected to Earth. All three leads are fed to the house. The center lead is called neutral because it is connected to earth. This means that there is little (ideally 0) voltage between it and earth. The other leads are 120 volts from the neutral and are called hot. If you were to touch one of them and something connected to earth you would agree that the name is appropriate. The 120 volt loads in the house are pretty much equally divided between the two hots and neutral. 240 Volt loads are connected between the two "hot" leads. Knowing which lead is hot is useful for safety.
Since you don't have 120 volts, I'm guessing that one side of a 240 volt winding is connected to earth and called neutral and the other side is hot. Again this is useful for safety.
Phil