240 volts
220 volts. In the US.
Household appliances usually have a voltage of either 110 or 220 volts; there should be a sticker somewhere that tells you the voltage for specific appliances. Make sure you don't plug it into the wrong voltage. Especially plugging an equipment designed for 110V into an outlet that gives 220V will burn your equipment.
Usually 220 to 240 VAC.
208 to 240 volts depending on your local power supply.
240 Volts. <><><> In USA, Canada and other countries using a similar 60 Hz houshold electricity supply system, they are dual-voltage. Some of their components, such as the timers, use 120 V while the heating element uses 240V.
An electric clothes dryer demands 22A from a 240V outlet at approximately 90% Power Factor. The power demand on the outlet should be about 240V x 22A x 0.9 = 4.75 kW. The active components in an electric clothes dryer are the heating element (100% PF) and the electric motor that turns the tumbler (70-80% PF). The formula you are looking for is W = I x E. (W is watts, I is current in amps, E is volts)
If the dryer is a clothes dryer then the short answer no. If it is a hair dryer then there might be a voltage switch on the handle that allows you to change voltages. If the manufacturer of the clothes dryer specified that it can be operated on dual voltages then it is just a matter of changing a few terminal connections. Check the instruction manual to see what it states there. This is very unlikely though. In North America all clothes dryers need 120/240 volts to operate. The 120 volts is used for the timer relays and for the drum motor, the 240 volts for the heating elements in the dryer. By changing to a higher voltage, it will not speed up the speed up the drying time. It is more likely that if you plug the dryer into the 240 volt receptacle it will burn the 120 volt motor out.
We know that Voltage = Current x Resistance, so if E = I x R, then E = 20 x 12 = 240 volts, and the dryer must be plugged into a 240 volt outlet.
You can look at the rating plate on each appliance and see how many watts it is. So for example a 1500 w hair dryer, or an 1100 w microwave oven. A stove and an electric clothes dryer use more than that (but I have gas for those appliances, so I cannot look). A refrigerator would use a lot too, but I cannot see the plate on that one either. If it does not list watts but lists amps, then: Volts * Amps = Watts. Note that the 'big' appliances like the stove and clothes dryer are usually 240 volts, not 120 V.
4800 watts because watts = volts x amps.
the voltage of the mains electricity in the UK