low5545 WROTE:I know that AC voltage directly from the plug is rated at 230V, 50Hz. But what is the Amp rating?
Besides, an AC plug has 3 pins (live, neutral, earth). What are their use? Is the earth pin connected to the metal casing of the circuit/product to prevent shock etc. ? The live wire carries AC voltage which is a sine wave ? The neutral to lead beck excess voltage back to the source (So is live like +, neutral is like - but just in AC ?)?
The Amp rating should be limited by the fuses mounted at the meters outside your house. The current is fed from the nearest sub-station where the step-down transformer is installed. I would guess it is capable of supplying thousands if not hundreds of Amps per phase. There are also fuses at the sub-station to protect the transformer which is oil-cooled.
I don't know why you are so concerned with the Earth Pin of the 3 pin plug. What I heard is that from the generators in TNB, there is no Live or Neutral, just 3 phase. The common point of the 3 phase electricity was connected to earthing system at the generator end and thus becomes the neutral of our single phase a/c. At the 3 pin plug of your house, the earth pin is connected to your local earth system by inserting a copper rod into the ground where the resistance is lowest near your house. This Earth will provide a fast return circuit if your heater has a leak to the chasis of your power appliances. That's why if you look outside your house, where the power is connected to your meter, there are only 2 wires from the TNB.
Allen