Why can't you simply use a step-up converter to plug a 240V appliance into a 120V socket?

Answer 1

The power rating on the converter won't be high enough. You cannot exceede the power capacity of the source, no matter how hard you try. In the US outlets are 15A at 120V. 15A * 120V = 1800W. No matter what you do, you cannot draw more power than that from the outlet. Also, you are limited by the weakest link in your chain. The next link is the converter itself. If you can get a converter with a power rating higher than your appliance, and the appliance draws under 1800W, then yes, you can power it with a converter. (Though, if it draws 1800W, or over 1500W to be practical, it will need a dedicated line.) So, for a small appliance bought overseas, yes this will work. For Ranges and Dryers, no it will not. There is a reason they are not designed to plug in to regular outlets. Range: 50A at 240V: 12,000 Watts max. 6.7x the amount of power a 120V outlet can supply. Dryer: 30A at 240V: 7,200 Watts max. 4 times the amount of power a 120V outlet can supply. The previous answer is not correct. Of course you can. There's absolutely no reason why it would not work. The outlet and the power source it is connected to has no limit as to the amount of power that can be drawn, for all intents and purposes. The current is artificially limited by the circuit's fuse/circuit breaker for safety reasons. Given sufficiently thick wire, the circuit can draw 50, 100, 200A with no problem. The reason the circuits are current-limited is due to the relatively thin wires between the power source and the outlet. Thinner wires heat up faster as the current passing through them increases. At a certain current level, the wire can heat up enough to be a fire hazard. A step-up transformer is simply wire wrapped around two iron cores. One side is connected to the 120V source (the outlet). The other side is connected to the appliance. The changing voltage on one side (AC) induces voltage changes on the other side proportional to the ratio of the number of turns of wire. This is basically the opposite of the step-down transformer connecting your house to the power grid. What would you use instead of a step-up transformer anyway?