Question about differing voltages in my house?
This post was written by admin on February 22, 2012
Posted Under: Heating
Posted Under: Heating
Most of the appliances and all of my light bulbs require 120 Volts. However, some appliances like my electric clothes drier, electric stove, and my central air conditioning system require 240 Volts. Why do these appliances work on a higher Voltage?
Reader Comments
The larger appliances take more power, and at a higher voltage, it is possible to obtain that power with smaller wire than would be needed at a lower voltage. Also, the conversion efficiency is higher.
They can use lighter gauge wire to carry the same amount of power. Using ohm’s law and its variations:
Power = Current x Voltage (P = I x E). If I double the power, I can cut the current in half and I’ll get the same power. Less current = smaller gauge wire. Lower cost of copper wire, easier to handle when wiring a house. Smaller motor for AC units. Your dryer drum motor runs off one leg of the 240 volt line (at 120 volts).
A dryer or water heater uses about 5,000 watts of power. That’s a little over 20 amps at 240 volts or a little over 40 amps at 120 volts.