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shekhar_dandya

basics of electrical supply

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Oh sorry, I forgot to mention that DC is worse than AC because it causes your mussels to cease up, put simply the lower the frequency the worse it gets.


It is all dependent upon the current that runs through you to ground, not the voltage or frequency.

I have a board that uses about 1,000 volts DC. Zaps you pretty hard, but causes no damage. (...it certainly wakes you up).

MP

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hi MP !
I think the 1000V source about which u are talking might be haveing a high internal resistance which dissipates most of the power when u touch the source.
It does happen .Some lineman do repair high voltage lines with bare hands but internal resistance must be high otherwise god is the savior!!! ;D

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Guest Alun

dent upon the current that runs through you to ground, not the voltage or frequency.

I have a board that uses about 1,000 volts DC. Zaps you pretty hard, but causes no damage. (...it certainly wakes you up).

I am aware of this MP, I meant to say that your body is less affected by current at higher frequencies because it doesn't affect the nervious system.

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hi MP !
I think the 1000V source about which u are talking might be haveing a high internal resistance which dissipates most of the power when u touch the source.


Prateeksikka, with a constant voltage source, resistance is what determines the amount of current in any circuit (V/R=I), including the body. Current is the same through a series circuit. Thus no matter which item, body or circuit, the total resistance of the circuit will determine the current.

MP

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Hi,
Iam back again with my original question.
Suppose I remove the ground plate that's buried under my building in a 5 feet deep ditch.keep the earth terminal floating in air.ie don't use it.
Now
expt #1: I hold the live wire.Do I get a shock?
expt#2:A person besides me on the same ground now holds the neutral and I hold the live.Now we both get shocked.right?
Are my observations correct?
What's the conclusion?
If U remove ground,no shock as far as one person is concerned.
When 2 persons hold,circuit gets completed and we both have  a shock.
So what is the importance of ground?

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Guest Yevgenip

Well, When you hold a Live wire your body's electrical Potential increases. If you are completely isolated from any thing that has a different potential than you have at the moment (220V or 110V or whatever), Nothing will Happen. If you touch something that has a much lower potential than you, you will get shocked - the bigger the potential defference - the bigger the voltage gets. The strenghth and nature of the shock depends also on the resistance between you and the object with the lower potential, since the resistance effects the current and it is the current, not the voltage that creates the shock and may kill you.

So it is possible to get a nice shock from a 1.5v source, if the current is strong enough.

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So it is possible to get a nice shock from a 1.5v source, if the current is strong enough.

Yevjeni
No, from 1.5v human wont get shock; coz body-resistance is high enogh compared to 1.5v to produce that much current accrding to ohm's law.
Aakaash
India

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Guest Alun

You won't be able to get a shock from 1.5V but you'll be able to feel it if you apply it to your tongue or if you have a cut. In my experiance the lowest voltage I've felt with my fingures is 24V but that's because it was hot and my fingures were sweaty.

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If there isn't any lightning around you, try touching both terminals of a telephone line with a single dry hand. You'll feel a tingle from its 51V if it is not in use.
Then have somebody call your telephone and the resulting ringing peaks of 178V at 10 Hz will make you smile, vibrate and jump away. The ringing is 90V/20 Hz but rides on top of the 51VDC, so the negative peak adds to the 51V each half-cycle. ;D

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Hi aakaash,

It sounds disastrous to me; you might get away with it if it was DC if you had a resistor in line with it but AC…no way! If the frequency is of sync, high current flows and something will blow! Maybe your inverter has some kind of sync for 50 or 60 Hz and voltage correction in it? ???

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You never connect the output of an inverter to the mains. As Ante says, the mains would blow it up! You plug a load like some lights into its output. If it powered your whole neighbourhood or city then it would be very overloaded!
Maybe you are thinking about a Un-interruptable Power Supply (UPS) that has a relay inside that switches the load from the mains to the output of an inverter when the mains fails. Then when the mains comes back on, the relay switches the load back to the mains.
The mains might be used to charge the battery in an inverter.

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