Generator sets produce either single or three phase power. You should use the type of power your panel provides. Residences and small business generally use single phase. Three-phase power is used for medium to large businesses especially where power is used for motor starting and running. Three phase generators are set up to produce 415V. Single-phase sets are 230V. Use the low voltage to run domestic appliances and the high voltage for your motors, heaters, stoves and dryers. Your service panel is either single phase or three phase, you don't need a three phase generator if your panel is only single phase. Check with your electrician before you begin your search.