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### AC Voltage

Posted: Thu Nov 03, 2011 5:25 pm
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 ?)?

### Re: AC Voltage

Posted: Fri Nov 04, 2011 9:45 am
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

### Re: AC Voltage

Posted: Fri Nov 04, 2011 2:29 pm
How about Yamaha generators like the picture below.

Where do they get their Earth pin connected?

### Re: AC Voltage

Posted: Wed Nov 09, 2011 8:25 pm
Many country AC does not come with Earth terminal, and some of the electrical device does not come with earth pin too. They can still function. Actually earth pin is for leakage, for safety.

### Re: AC Voltage

Posted: Wed Nov 30, 2011 12:38 am
The earth wire is connected to the metal casing as well for safety =) This earth wire will be grounded.