The United States and Canada use 120 V rms as the standard household voltage, while most of the rest of the world uses 240 V rms for the household standard. What are the advantages and disadvantages of the two systems?
The United States and Canada use 120 V rms as the standard household voltage, while most of the rest of the world uses 240 V rms for the household standard. What are the advantages and disadvantages of the two systems?
120 V rms as the standard household voltage
Advantages-
a) If a person touched a live wire so less current would flow and hence 120V system is safe.
Disadvantages-
A) Power loss = I2Rt where I = current, R= Resistance and t= time.
Since power loss is directly proportional to square of current with more supplied current, power loss will increase and with 120V system, greater current must be supplied to an appliance to deliver the same amount of power. Therefore, it increases power.
b) Thicker wires have low resistance so at 120V or lower voltages electrical cables have to be thicker to reduce power losses and hence cost of electrical transmission increases.
C) Generally120 V systems operate at 60Hz so at this high frequency, generators need to rotate at higher speed, so more wear and tear of the rotating parts and hence more cost of equipments as they bear more stress.
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
