Switching on a transformer without a load connected to the secondary will not cause it to burn, as it operates cooler without a load, provided the voltage remains the same. In this state, the transformer acts as an inductance, with current influenced by supply voltage, frequency, and primary winding characteristics. Appliances often keep the primary connected to mains, which can waste power and expose the primary to voltage surges. The discussion also highlights that voltage transformers are designed for specific frequencies, making them unsuitable for variable outputs like those from wind turbine alternators. Proper safety precautions are emphasized when working with hazardous voltages.