Adding 220v welding circuit to the shop/garage

[LD1]

Voltage is what jumps. A spark plug works because of high voltage, lightning strikes because of high voltage. The simple fact is voltage and amps are tied together.

Just saying it's the amps that kill you is only sort of true. For the amps to kill you it must get to your heart. The human body has a fixed resistance, you can drop it when you wet your skin, but let's assume you are not stingin knee deep in water in the pouring rain working on an AC panel.

If you have ever heard of ohm's law you know that V(volts)=I(amps)xR(resistance). If the resistance stays the same and you increase the voltage then you decrease the amps needed. And like Mace pointed out it only takes a small amount of current, 75mA to kill, if it reaches your heart. I avoided the effects of frequency to simplify things.

In the real world when ever you see that sign it means that high voltage and high current, beware.

You hit the nail on the head:thumbsup:

It takes BOTH to kill you. Amps are what does the damage, but the volts are what get it to where it CAN do te damage. Without the volts, the AMPS can NOT make it to the "kill zone"

Just try touching BOTH of your battery terminals the same time. I doubt you would even feel that ~800+ AMPS. But it takes VERY little amps @480V and your cooked:confused2:

 

[beppington]

Not that I really understand water pressure / hydraulics either, but could we relate this to a water hose?

High pressure with low volume could injure you since it could potentially drill a hole in you.

High volume with low pressure isn't likely to do anything more than push you over.

The pressure would be equal to voltage, & volume would be equal to amperage.

Is this correct?

 

[KennyG]

Not that I really understand water pressure / hydraulics either, but could we relate this to a water hose?

High pressure with low volume could injure you since it could potentially drill a hole in you.

High volume with low pressure isn't likely to do anything more than push you over.

The pressure would be equal to voltage, & volume would be equal to amperage.

Is this correct?

This isn't exactly the analogy I would use. There is another factor here, resistance. As most people know, voltage below a certain level won't affect a person because of the surface resistance of the skin. This is why you can grab both terminals of a 12 volt battery (which has tremendous current potential) and not feel it. However, as the voltage gets up above about 40 volts, it will be conducted by the skin and, with enough amperage, pass through the heart and disrupt the nervous system (i.e. paralysis or death).

I'm sure you've heard of someone who has been injured by a 12 volt battery. Usually the reason is that they shorted across the terminals with a good conductor (metal tool) and the rapid heating/sparking burned them.

It's not that hard to work safely around electricity but you have to remember that both voltage and amperage are important, but in different ways. You can't get casual about it. I remember a story about an old electrician who could flick his fingers across two conductors and say "110" or "220". One day he got into some high voltage and everyone wondered if his last words were "4160".

 

[beppington]

This isn't exactly the analogy I would use. There is another factor here, resistance.

Skin has a resistance to water puncturing it, too.

As most people know, voltage below a certain level won't affect a person because of the surface resistance of the skin.

Similarly, in my high pressure / low volume jet stream of water scenario, a water pressure below a certain level wouldn't affect a person, also because of the surface resistance of the skin. You would just be spraying a water stream on skin with no damage being done. And as you increase the pressure, the skin would push in more & more & more, until it breaks.

However, as the voltage gets up above about 40 volts, it will be conducted by the skin and, with enough amperage, pass through the heart and disrupt the nervous system (i.e. paralysis or death).

Similarly, as the water pressure increases beyond a level the skin can deflect, the jet stream of water would cut the skin & begin to do damage within.

I'm mostly "thinkin' aloud" here, not trying to be argumentative. Does this not make sense, though?

 

[nickel plate]

Well thanks all-I think I got more information than I asked for but do go full steam ahead as I am the OP and I do endorse all comments posted past and future on this thread!

 

[beppington]

Well thanks all-I think I got more information than I asked for but do go full steam ahead as I am the OP and I do endorse all comments posted past and future on this thread!

Yeah, sorry about that. I realized after hitting submit that I (we?) had fully stolen your thread. Thanks for not mindin'! :thumbsup:

 

[Mace Canute]

I'm sure you've heard of someone who has been injured by a 12 volt battery. Usually the reason is that they shorted across the terminals with a good conductor (metal tool) and the rapid heating/sparking burned them.

Years ago, back in the mid 70's I heard of an old farmer who was killed by electrocution from a battery. It was combining time...hot weather...and he was boosting his combine to get it started. No one actually saw what happened but as best they could figure, he had hooked up one end of his cables and was in the process of hooking up the other end by squeezing both clamps at the same time to put them on the posts. His clamps were old and had lost insulation on them, enough that both his hands contacted metal, and it appeared that the high pressure he put on the clamps combined with sweaty hands was enough to lower his resistance to the point that enough current flowed to stop either his heart or his breathing.

I remember a story about an old electrician who could flick his fingers across two conductors and say "110" or "220". One day he got into some high voltage and everyone wondered if his last words were "4160".

That's kinda funny in a macabre sort of way...

 

[grsthegreat]

That's kinda funny in a macabre sort of way...

kinda like "Here, hold my beer and watch this"

 

[LD1]

kinda like "Here, hold my beer and watch this"

:laughing::laughing::laughing::laughing: