As Roy said you need a 55-0-55 centre tap transformer where the centre tap is earthed. This ensures that the voltage on the equipment is never more than 55 volts with respect to earth. Even if you have a hand in the water and touch the live terminal, you may get a belt but it should not be fatal. But don't try it.
Still much safer to get a centre tapped site transformer for safety - also have a look in Exchange and Mart, where you will find quite a number of suppliers.