Dangers of high current/voltage?

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High voltage and high electrical current are only dangerous when they exceed circuit capacity or when individuals lack proper knowledge. High voltage itself is not intrinsically hazardous; for instance, a Van de Graaff generator can produce thousands of volts safely. However, when a circuit is opened under load, as demonstrated in a linked video, it can lead to dangerous situations like plasma fireballs. The real danger to living beings arises from the power involved, particularly when current flows across the body, which can be lethal. Understanding the principles of electricity is crucial for safety in handling high voltage and current situations.
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Why is high voltage dangerous in a circuit? Similarly, why is high electrical current dangerous in a circuit?
 
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user111_23 said:
Why is high voltage dangerous in a circuit?
It's only dangerous if it exceeds the circuit capacity, or someone does not know what they are doing.
Like the squirrel: http://www.youtube.com/watch?v=0XBurkUkdFE&NR=1
Someone who knows what they doing can hang onto 500,000 volts:

Similarly, why is high electrical current dangerous in a circuit?
Same answer: It's only dangerous if it exceeds the circuit capacity, or someone does not know what they are doing.

The following two gentlemen appear to have opened a circuit breaker which had a large current flowing through it: http://www.youtube.com/watch?v=h10ALIpD0R4&feature=related

As long as the circuit was closed, thousands of amps could flow safely. As soon as the switch was opened, a plasma fireball was ejected, which probably injured the two men.
 
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In terms of danger to living beings, high voltage isn't intrinsically dangerous. A Van de Graaff generator can easily create potential difference of thousands of volts and more, and yet is safe (although I wouldn't want to touch a charged one!). It's the power (P=I^2*R=V^2/R) that fries you if you happen to touch a bare wire.
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Burns from electrical contact can be treated. Enough current (more than a few milliamps) flowing across your upper torso (like from hand to hand, or hand to foot) can stop your heart.
 
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