Almost feel embarassed, having been an engineer at one time. But I've though up a scheme which seems like it'd work great which means it's fraught with peril. For a temporary connection of a fuel powered generator into the mains of a house (without installing alot of switchgear) is there any hazard in the following (assuming the generator is properly grounded, etc.): The generator has a 240V standard 4-Prong 30A output and the dryer line in the house has a standard 4-Prong 240 30A plug. Both have circuit breakers at 30A and the ampacity of the lines for the dryer exceeds this (i.e. no overcurrent or overheating problem in the lines, and all the lines are protected by CB). Would there be any problem with turning off the main breaker (thus isolating the bus in the house from the outside electrical mains), Plugging the output of the generator into a 4-prong output plug and plugging this into the dryer outlet (assuming all the wires were correctly connected). The power would then be flowing in from the dryer connection to the mains of the house and could power them and an appropriate wattage/VA of household items ? All house lines are equipped with GFI.